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DataListCommandEventArgs Class

Provides data for the CancelCommand, DeleteCommand, EditCommand, ItemCommand, and UpdateCommand events of the DataList control. This class cannot be inherited.

For a list of all members of this type, see DataListCommandEventArgs Members.

System.Object
   System.EventArgs
      System.Web.UI.WebControls.CommandEventArgs
         System.Web.UI.WebControls.DataListCommandEventArgs

[Visual Basic]
NotInheritable Public Class DataListCommandEventArgs
   Inherits CommandEventArgs
[C#]
public sealed class DataListCommandEventArgs : CommandEventArgs
[C++]
public __gc __sealed class DataListCommandEventArgs : public
   CommandEventArgs
[JScript]
public class DataListCommandEventArgs extends CommandEventArgs

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Remarks

The CancelCommand event is raised when the Cancel button for an item in the DataList control is clicked.

The DeleteCommand event is raised when the Delete button for an item in the DataList control is clicked.

The EditCommand event is raised when the Edit button for an item in the DataList control is clicked.

The ItemCommand event is raised when any button for an item in the DataList control is clicked. This allows you to programmatically test for when a specific command button is clicked and take appropriate action. This event is commonly used to handle custom command buttons for the DataList control.

The UpdateCommand event is raised when the Update button for an item in the DataList control is clicked.

For a list of initial property values for an instance of DataListCommandEventArgs, see the DataListCommandEventArgs constructor.

For more information about handling events, see Consuming Events.

Example

[Visual Basic, C#] The following example demonstrates how to specify and code a handler for the ItemCommand event. It creates a custom button that displays additional information about a selected item in the DataList control. The information is displayed by using the SelectedItemTemplate property.

[Visual Basic] 
<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<html>
<head>
 
   <script language="VB" runat="server">
 
    Function CreateDataSource() As ICollection
        
        Dim dt As New DataTable()
        Dim dr As DataRow
        
        ' Create a DataTable.
        dt.Columns.Add(New DataColumn("IntegerValue", GetType(Int32)))
        dt.Columns.Add(New DataColumn("StringValue", GetType(String)))
        dt.Columns.Add(New DataColumn("DateTimeValue", GetType(DateTime)))
        
        ' Create sample data.
        Dim i As Integer
        For i = 1 To 9
            dr = dt.NewRow()
            dr(0) = i
            dr(1) = "Item " & i.ToString()
            dr(2) = DateTime.Now.ToShortTimeString()
            dt.Rows.Add(dr)
        Next i
        
        
        ' Return a DataView to the DataTable.
        Dim dv As New DataView(dt)
        Return dv
    End Function 'CreateDataSource
     

    Sub Page_Load(sender As Object, e As EventArgs)
        
        If Not IsPostBack Then
            BindList()
        End If 
    End Sub 'Page_Load


    Sub BindList()
        
        DataList1.DataSource = CreateDataSource()
        DataList1.DataBind()
    End Sub 'BindList
     

    Sub DataList_ItemCommand(sender As Object, e As DataListCommandEventArgs)
        If CType(e.CommandSource, LinkButton).CommandName = "select" Then
            DataList1.SelectedIndex = e.Item.ItemIndex
        End If 
        BindList()
    End Sub 'DataList_ItemCommand
     
   </script>
 
</head>
<body>
 
   <form runat=server>

      <h3>DataListCommandEventArgs Example</h3>
 
      <asp:DataList id="DataList1"                                                
                    GridLines="Both"                                                       
                    OnItemCommand="DataList_ItemCommand"
                    runat="server">

         <HeaderTemplate>
            Items
         </HeaderTemplate>

         <ItemTemplate>
            <asp:LinkButton id="button1"
                            Text="Show details" 
                            CommandName="select" 
                            runat="server"/>
            <%# DataBinder.Eval(Container.DataItem, "StringValue") %>
         </ItemTemplate>

         <SelectedItemTemplate>
            Item:
            <%# DataBinder.Eval(Container.DataItem, "StringValue") %>
            <br>
            Order Date:
            <%# DataBinder.Eval(Container.DataItem, "DateTimeValue", "{0:d}") %>
            <br>
            Quantity:
            <%# DataBinder.Eval(Container.DataItem, "IntegerValue", "{0:N1}") %>
            <br>
         </SelectedItemTemplate>
 
      </asp:DataList>

   </form>
 
</body>
</html>
   

[C#] 
<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<html>
<head>
 
   <script language="c#" runat="server">
 
      ICollection CreateDataSource() 
      {
         
         DataTable dt = new DataTable();
         DataRow dr;
 
         // Create a DataTable.
         dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
         dt.Columns.Add(new DataColumn("StringValue", typeof(string)));
         dt.Columns.Add(new DataColumn("DateTimeValue", typeof(DateTime)));
 
         // Create sample data.
         for (int i = 1; i <= 9; i++) 
         {
            dr = dt.NewRow();
            dr[0] = i;
            dr[1] = "Item " + i.ToString();
            dr[2] = DateTime.Now.ToShortTimeString();
            dt.Rows.Add(dr);
         }
          
 
         // Return a DataView to the DataTable.
         DataView dv = new DataView(dt);
         return dv;
         
      }
 
      void Page_Load(Object sender, EventArgs e) 
      {
         
         if (!IsPostBack)
            BindList();
 
      }
 
      void BindList() 
      {

         DataList1.DataSource = CreateDataSource();
         DataList1.DataBind();

      }
     
      void DataList_ItemCommand(object sender, DataListCommandEventArgs e) 
      {          
         if (((LinkButton)e.CommandSource).CommandName == "select")
            DataList1.SelectedIndex = e.Item.ItemIndex;
         
         BindList();
      }
 
   </script>
 
</head>
<body>
 
   <form runat=server>

      <h3>DataListCommandEventArgs Example</h3>
 
      <asp:DataList id="DataList1"                                                
                    GridLines="Both"                                                       
                    OnItemCommand="DataList_ItemCommand"
                    runat="server">

         <HeaderTemplate>
            Items
         </HeaderTemplate>

         <ItemTemplate>
            <asp:LinkButton id="button1"
                            Text="Show details" 
                            CommandName="select" 
                            runat="server"/>
            <%# DataBinder.Eval(Container.DataItem, "StringValue") %>
         </ItemTemplate>

         <SelectedItemTemplate>
            Item:
            <%# DataBinder.Eval(Container.DataItem, "StringValue") %>
            <br>
            Order Date:
            <%# DataBinder.Eval(Container.DataItem, "DateTimeValue", "{0:d}") %>
            <br>
            Quantity:
            <%# DataBinder.Eval(Container.DataItem, "IntegerValue", "{0:N1}") %>
            <br>
         </SelectedItemTemplate>
 
      </asp:DataList>

   </form>
 
</body>
</html>
   

[Visual Basic] 

<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>

<html>
<head>

   <script runat="server">

      ' The Cart and CartView objects temporarily store the data source
      ' for the DataList control while the page is being processed.
      Dim Cart As DataTable = New DataTable()
      Dim CartView As DataView
 
      Sub Page_Load(sende As Object, e As EventArgs) 
 
         ' With a database, use an select query to retrieve the data.
         ' Because the data source in this example is an in-memory
         ' DataTable, retrieve the data from session state if it exists;
         ' otherwise, create the data source.
         GetSource()

         ' The DataGrid control maintains state between posts to the server;
         ' it only needs to be bound to a data source the first time the
         ' page is loaded or when the data source is updated.
         If Not IsPostBack Then

            BindList()

         End If
                   
      End Sub

      Sub BindList() 

         ' Set the data source and bind to the DataList control.
         ItemsList.DataSource = CartView
         ItemsList.DataBind()

      End Sub

      Sub GetSource()

         ' For this example, the data source is a DataTable that
         ' is stored in session state. If the data source does not exist,
         ' create it; otherwise, load the data.
         If Session("ShoppingCart") Is Nothing Then 

            ' Create the sample data.
            Dim dr As DataRow  
 
            ' Define the columns of the table.
            Cart.Columns.Add(new DataColumn("Qty", GetType(Int32)))
            Cart.Columns.Add(new DataColumn("Item", GetType(String)))
            Cart.Columns.Add(new DataColumn("Price", GetType(Double)))

            ' Store the table in session state to persist its values
            ' between posts to the server.
            Session("ShoppingCart") = Cart
             
            ' Populate the DataTable with sample data.
            Dim i As Integer

            For i = 1 To 9 
            
               dr = Cart.NewRow()
               If (i Mod 2) <> 0 Then

                  dr(0) = 2
               
               Else
               
                  dr(0) = 1
               
               End If

               dr(1) = "Item " & i.ToString()
               dr(2) = (1.23 * (i + 1))
               Cart.Rows.Add(dr)
            
            Next i

         Else

            ' Retrieve the sample data from session state.
            Cart = CType(Session("ShoppingCart"), DataTable)

         End If         
 
         ' Create a DataView and specify the field to sort by.
         CartView = New DataView(Cart)
         CartView.Sort="Item"

         Return

      End Sub

      Sub Edit_Command(sender As Object, e As DataListCommandEventArgs) 

         ' Set the EditItemIndex property to the index of the item clicked
         ' in the DataList control to enable editing for that item. Be sure
         ' to rebind the DataList to the data source to refresh the control.
         ItemsList.EditItemIndex = e.Item.ItemIndex
         BindList()

      End Sub

      Sub Cancel_Command(sender As Object, e As DataListCommandEventArgs) 

         ' Set the EditItemIndex property to -1 to exit editing mode. Be sure
         ' to rebind the DataList to the data source to refresh the control.
         ItemsList.EditItemIndex = -1
         BindList()

      End Sub

      Sub Delete_Command(sender As Object, e As DataListCommandEventArgs) 

         ' Retrieve the name of the item to remove.
         Dim item As String = (CType(e.Item.FindControl("ItemLabel"), Label)).Text

         ' Filter the CartView for the selected item and remove it from
         ' the data source.
         CartView.RowFilter = "Item='" & item & "'"
         If CartView.Count > 0 Then 
       
            CartView.Delete(0)
         
         End If
         CartView.RowFilter = ""

         ' Set the EditItemIndex property to -1 to exit editing mode. Be sure 
         ' to rebind the DataList to the data source to refresh the control.
         ItemsList.EditItemIndex = -1
         BindList()

      End Sub

      Sub Update_Command(sender As Object, e As DataListCommandEventArgs) 

         ' Retrieve the updated values from the selected item.
         Dim item As String = _
             (CType(e.Item.FindControl("ItemLabel"), Label)).Text
         Dim qty As String = _
             (CType(e.Item.FindControl("QtyTextBox"), TextBox)).Text
         Dim price As String = _
             (CType(e.Item.FindControl("PriceTextBox"), TextBox)).Text

         ' With a database, use an update command to update the data.
         ' Because the data source in this example is an in-memory 
         ' DataTable, delete the old row and replace it with a new one.

         ' Filter the CartView for the selected item and remove it from 
         ' the data source.
         CartView.RowFilter = "Item='" & item & "'"
         If CartView.Count > 0 Then 
       
            CartView.Delete(0)
         
         End If
         CartView.RowFilter = ""

         ' ***************************************************************
         ' Insert data validation code here. Make sure to validate the
         ' values entered by the user before converting to the appropriate
         ' data types and updating the data source.
         ' ***************************************************************

         ' Add a new entry to replace the previous item.
         Dim dr As DataRow = Cart.NewRow()
         dr(0) = qty
         dr(1) = item
         ' If necessary, remove the '$' character from the price before 
         ' converting the price to a Double.
         If price.Chars(0) = "$" Then

            dr(2) = Convert.ToDouble(price.Substring(1))

         Else

            dr(2) = Convert.ToDouble(price)
         
         End If

         Cart.Rows.Add(dr)

         ' Set the EditItemIndex property to -1 to exit editing mode. 
         ' Be sure to rebind the DataList to the data source to refresh 
         ' the control.
         ItemsList.EditItemIndex = -1
         BindList()

      End Sub

   </script>

</head>
<body>

   <form runat=server>

      <h3>DataList Edit Example</h3>

      Click <b>Edit</b> to edit the values of the item.

      <br><br>
       
      <asp:DataList id="ItemsList"
           GridLines="Both"
           RepeatColumns="3"
           RepeatDirection="Horizontal"
           CellPadding="3"
           CellSpacing="0"
           OnEditCommand="Edit_Command"
           OnUpdateCommand="Update_Command"
           OnDeleteCommand="Delete_Command"
           OnCancelCommand="Cancel_Command"
           runat="server">

         <HeaderStyle BackColor="#aaaadd">
         </HeaderStyle>

         <AlternatingItemStyle BackColor="Gainsboro">
         </AlternatingItemStyle>

         <EditItemStyle BackColor="yellow">
         </EditItemStyle>

         <HeaderTemplate>

            Items

         </HeaderTemplate>
         
         <ItemTemplate>

            Item:
            <%# DataBinder.Eval(Container.DataItem, "Item") %> 

            <br>

            Quantity:
            <%# DataBinder.Eval(Container.DataItem, "Qty") %>

            <br>

            Price:
            <%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}") %>

            <br>

            <asp:LinkButton id="EditButton" 
                 Text="Edit" 
                 CommandName="Edit"
                 runat="server"/>

         </ItemTemplate>
              
         <EditItemTemplate>

            Item:
            <asp:Label id="ItemLabel" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Item") %>' 
                 runat="server"/>

            <br>

            Quantity:
            <asp:TextBox id="QtyTextBox" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Qty") %>' 
                 runat="server"/>

            <br>

            Price:
            <asp:TextBox id="PriceTextBox" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}") %>' 
                 runat="server"/>

            <br>

            <asp:LinkButton id="UpdateButton" 
                 Text="Update" 
                 CommandName="Update" 
                 runat="server"/>

            <asp:LinkButton id="DeleteButton" 
                 Text="Delete" 
                 CommandName="Delete" 
                 runat="server"/>

            <asp:LinkButton id="CancelButton" 
                 Text="Cancel" 
                 CommandName="Cancel" 
                 runat="server"/>

         </EditItemTemplate>

      </asp:DataList>

   </form>

</body>
</html>


[C#] 

<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>

<html>
<head>

   <script runat="server">

      // The Cart and CartView objects temporarily store the data source
      // for the DataList control while the page is being processed.
      DataTable Cart = new DataTable();
      DataView CartView;   
 
      void Page_Load(Object sender, EventArgs e) 
      {
 
         // With a database, use an select query to retrieve the data. 
         // Because the data source in this example is an in-memory
         // DataTable, retrieve the data from session state if it exists;
         // otherwise, create the data source.
         GetSource();

         // The DataList control maintains state between posts to the server;
         // it only needs to be bound to a data source the first time the
         // page is loaded or when the data source is updated.
         if (!IsPostBack)
         {

            BindList();

         }
                   
      }

      void BindList() 
      {

         // Set the data source and bind to the DataList control.
         ItemsList.DataSource = CartView;
         ItemsList.DataBind();

      }

      void GetSource()
      {

         // For this example, the data source is a DataTable that 
         // is stored in session state. If the data source does not exist,
         // create it; otherwise, load the data.
         if (Session["ShoppingCart"] == null) 
         {     

            // Create the sample data.
            DataRow dr;  
 
            // Define the columns of the table.
            Cart.Columns.Add(new DataColumn("Qty", typeof(Int32)));
            Cart.Columns.Add(new DataColumn("Item", typeof(String)));
            Cart.Columns.Add(new DataColumn("Price", typeof(Double)));

            // Store the table in session state to persist its values 
            // between posts to the server.
            Session["ShoppingCart"] = Cart;
             
            // Populate the DataTable with sample data.
            for (int i = 1; i <= 9; i++) 
            {
               dr = Cart.NewRow();
               if (i % 2 != 0)
               {
                  dr[0] = 2;
               }
               else
               {
                  dr[0] = 1;
               }
               dr[1] = "Item " + i.ToString();
               dr[2] = (1.23 * (i + 1));
               Cart.Rows.Add(dr);
            }

         } 

         else
         {

            // Retrieve the sample data from session state.
            Cart = (DataTable)Session["ShoppingCart"];

         }         
 
         // Create a DataView and specify the field to sort by.
         CartView = new DataView(Cart);
         CartView.Sort="Item";

         return;

      }

      void Edit_Command(Object sender, DataListCommandEventArgs e) 
      {

         // Set the EditItemIndex property to the index of the item clicked
         // in the DataList control to enable editing for that item. Be sure
         // to rebind the DataList to the data source to refresh the control.
         ItemsList.EditItemIndex = e.Item.ItemIndex;
         BindList();

      }

      void Cancel_Command(Object sender, DataListCommandEventArgs e) 
      {

         // Set the EditItemIndex property to -1 to exit editing mode. Be sure
         // to rebind the DataList to the data source to refresh the control.
         ItemsList.EditItemIndex = -1;
         BindList();

      }

      void Delete_Command(Object sender, DataListCommandEventArgs e) 
      { 

         // Retrieve the name of the item to remove.
         String item = ((Label)e.Item.FindControl("ItemLabel")).Text;

         // Filter the CartView for the selected item and remove it from
         // the data source.
         CartView.RowFilter = "Item='" + item + "'";
         if (CartView.Count > 0) 
         {
            CartView.Delete(0);
         }
         CartView.RowFilter = "";

         // Set the EditItemIndex property to -1 to exit editing mode. Be sure
         // to rebind the DataList to the data source to refresh the control.
         ItemsList.EditItemIndex = -1;
         BindList();

      }

      void Update_Command(Object sender, DataListCommandEventArgs e) 
      {

         // Retrieve the updated values from the selected item.
         String item = ((Label)e.Item.FindControl("ItemLabel")).Text;
         String qty = ((TextBox)e.Item.FindControl("QtyTextBox")).Text;
         String price = ((TextBox)e.Item.FindControl("PriceTextBox")).Text;

         // With a database, use an update command to update the data.
         // Because the data source in this example is an in-memory 
         // DataTable, delete the old row and replace it with a new one.

         // Filter the CartView for the selected item and remove it from
         // the data source.
         CartView.RowFilter = "Item='" + item + "'";
         if (CartView.Count > 0)
         {
            CartView.Delete(0);
         }
         CartView.RowFilter = "";

         // ***************************************************************
         // Insert data validation code here. Make sure to validate the
         // values entered by the user before converting to the appropriate
         // data types and updating the data source.
         // ***************************************************************

         // Add a new entry to replace the previous item.
         DataRow dr = Cart.NewRow();
         dr[0] = qty;
         dr[1] = item;
         // If necessary, remove the '$' character from the price before
         // converting the price to a Double.
         if(price[0] == '$')
         {
            dr[2] = Convert.ToDouble(price.Substring(1));
         }
         else
         {
            dr[2] = Convert.ToDouble(price);
         }
         Cart.Rows.Add(dr);

         // Set the EditItemIndex property to -1 to exit editing mode. 
         // Be sure to rebind the DataList to the data source to refresh
         // the control.
         ItemsList.EditItemIndex = -1;
         BindList();

      }

   </script>

</head>
<body>

   <form runat=server>

      <h3>DataList Edit Example</h3>

      Click <b>Edit</b> to edit the values of the item.

      <br><br>
       
      <asp:DataList id="ItemsList"
           GridLines="Both"
           RepeatColumns="3"
           RepeatDirection="Horizontal"
           CellPadding="3"
           CellSpacing="0"
           OnEditCommand="Edit_Command"
           OnUpdateCommand="Update_Command"
           OnDeleteCommand="Delete_Command"
           OnCancelCommand="Cancel_Command"
           runat="server">

         <HeaderStyle BackColor="#aaaadd">
         </HeaderStyle>

         <AlternatingItemStyle BackColor="Gainsboro">
         </AlternatingItemStyle>

         <EditItemStyle BackColor="yellow">
         </EditItemStyle>

         <HeaderTemplate>

            Items

         </HeaderTemplate>
         
         <ItemTemplate>

            Item:
            <%# DataBinder.Eval(Container.DataItem, "Item") %> 

            <br>

            Quantity:
            <%# DataBinder.Eval(Container.DataItem, "Qty") %>

            <br>

            Price:
            <%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}") %>

            <br>

            <asp:LinkButton id="EditButton" 
                 Text="Edit" 
                 CommandName="Edit"
                 runat="server"/>

         </ItemTemplate>
              
         <EditItemTemplate>

            Item:
            <asp:Label id="ItemLabel" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Item") %>' 
                 runat="server"/>

            <br>

            Quantity:
            <asp:TextBox id="QtyTextBox" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Qty") %>' 
                 runat="server"/>

            <br>

            Price:
            <asp:TextBox id="PriceTextBox" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}") %>' 
                 runat="server"/>

            <br>

            <asp:LinkButton id="UpdateButton" 
                 Text="Update" 
                 CommandName="Update" 
                 runat="server"/>

            <asp:LinkButton id="DeleteButton" 
                 Text="Delete" 
                 CommandName="Delete" 
                 runat="server"/>

            <asp:LinkButton id="CancelButton" 
                 Text="Cancel" 
                 CommandName="Cancel" 
                 runat="server"/>

         </EditItemTemplate>

      </asp:DataList>

   </form>

</body>
</html>


[Visual Basic] 

<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>

<html>
<head>

   <script runat="server">

      ' The Cart and CartView objects temporarily store the data source
      ' for the DataList control while the page is being processed.
      Dim Cart As DataTable = New DataTable()
      Dim CartView As DataView
 
      Sub Page_Load(sende As Object, e As EventArgs) 
 
         ' With a database, use an select query to retrieve the data.
         ' Because the data source in this example is an in-memory
         ' DataTable, retrieve the data from session state if it exists;
         ' otherwise, create the data source.
         GetSource()

         ' The DataGrid control maintains state between posts to the server;
         ' it only needs to be bound to a data source the first time the
         ' page is loaded or when the data source is updated.
         If Not IsPostBack Then

            BindList()

         End If

         ' Manually register the event-handling methods.
         AddHandler ItemsList.EditCommand, AddressOf Edit_Command
         AddHandler ItemsList.UpdateCommand, AddressOf Update_Command
         AddHandler ItemsList.DeleteCommand, AddressOf Delete_Command
         AddHandler ItemsList.CancelCommand, AddressOf Cancel_Command
                   
      End Sub

      Sub BindList() 

         ' Set the data source and bind to the DataList control.
         ItemsList.DataSource = CartView
         ItemsList.DataBind()

      End Sub

      Sub GetSource()

         ' For this example, the data source is a DataTable that
         ' is stored in session state. If the data source does not exist,
         ' create it; otherwise, load the data.
         If Session("ShoppingCart") Is Nothing Then 

            ' Create the sample data.
            Dim dr As DataRow  
 
            ' Define the columns of the table.
            Cart.Columns.Add(new DataColumn("Qty", GetType(Int32)))
            Cart.Columns.Add(new DataColumn("Item", GetType(String)))
            Cart.Columns.Add(new DataColumn("Price", GetType(Double)))

            ' Store the table in session state to persist its values
            ' between posts to the server.
            Session("ShoppingCart") = Cart
             
            ' Populate the DataTable with sample data.
            Dim i As Integer

            For i = 1 To 9 
            
               dr = Cart.NewRow()
               If (i Mod 2) <> 0 Then

                  dr(0) = 2
               
               Else
               
                  dr(0) = 1
               
               End If

               dr(1) = "Item " & i.ToString()
               dr(2) = (1.23 * (i + 1))
               Cart.Rows.Add(dr)
            
            Next i

         Else

            ' Retrieve the sample data from session state.
            Cart = CType(Session("ShoppingCart"), DataTable)

         End If         
 
         ' Create a DataView and specify the field to sort by.
         CartView = New DataView(Cart)
         CartView.Sort="Item"

         Return

      End Sub

      Sub Edit_Command(sender As Object, e As DataListCommandEventArgs) 

         ' Set the EditItemIndex property to the index of the item clicked
         ' in the DataList control to enable editing for that item. Be sure
         ' to rebind the DataList to the data source to refresh the control.
         ItemsList.EditItemIndex = e.Item.ItemIndex
         BindList()

      End Sub

      Sub Cancel_Command(sender As Object, e As DataListCommandEventArgs) 

         ' Set the EditItemIndex property to -1 to exit editing mode. Be sure
         ' to rebind the DataList to the data source to refresh the control.
         ItemsList.EditItemIndex = -1
         BindList()

      End Sub

      Sub Delete_Command(sender As Object, e As DataListCommandEventArgs) 

         ' Retrieve the name of the item to remove.
         Dim item As String = (CType(e.Item.FindControl("ItemLabel"), Label)).Text

         ' Filter the CartView for the selected item and remove it from 
         ' the data source.
         CartView.RowFilter = "Item='" & item & "'"
         If CartView.Count > 0 Then 
       
            CartView.Delete(0)
         
         End If
         CartView.RowFilter = ""

         ' Set the EditItemIndex property to -1 to exit editing mode. Be sure 
         ' to rebind the DataList to the data source to refresh the control.
         ItemsList.EditItemIndex = -1
         BindList()

      End Sub

      Sub Update_Command(sender As Object, e As DataListCommandEventArgs) 

         ' Retrieve the updated values from the selected item.
         Dim item As String = _
             (CType(e.Item.FindControl("ItemLabel"), Label)).Text
         Dim qty As String = _
             (CType(e.Item.FindControl("QtyTextBox"), TextBox)).Text
         Dim price As String = _
             (CType(e.Item.FindControl("PriceTextBox"), TextBox)).Text

         ' With a database, use an update command to update the data.
         ' Because the data source in this example is an in-memory 
         ' DataTable, delete the old row and replace it with a new one.

         ' Filter the CartView for the selected item and remove it from 
         ' the data source.
         CartView.RowFilter = "Item='" & item & "'"
         If CartView.Count > 0 Then 
       
            CartView.Delete(0)
         
         End If
         CartView.RowFilter = ""

         ' ***************************************************************
         ' Insert data validation code here. Make sure to validate the
         ' values entered by the user before converting to the appropriate
         ' data types and updating the data source.
         ' ***************************************************************

         ' Add a new entry to replace the previous item.
         Dim dr As DataRow = Cart.NewRow()
         dr(0) = qty
         dr(1) = item
         ' If necessary, remove the '$' character from the price before 
         ' converting the price to a Double.
         If price.Chars(0) = "$" Then

            dr(2) = Convert.ToDouble(price.Substring(1))

         Else

            dr(2) = Convert.ToDouble(price)
         
         End If

         Cart.Rows.Add(dr)

         ' Set the EditItemIndex property to -1 to exit editing mode. 
         ' Be sure to rebind the DataList to the data source to refresh 
         ' the control.
         ItemsList.EditItemIndex = -1
         BindList()

      End Sub

   </script>

</head>
<body>

   <form runat=server>

      <h3>DataList Edit Example</h3>

      Click <b>Edit</b> to edit the values of the item.

      <br><br>
       
      <asp:DataList id="ItemsList"
           GridLines="Both"
           RepeatColumns="3"
           RepeatDirection="Horizontal"
           CellPadding="3"
           CellSpacing="0"
           OnEditCommand="Edit_Command"
           OnUpdateCommand="Update_Command"
           OnDeleteCommand="Delete_Command"
           OnCancelCommand="Cancel_Command"
           runat="server">

         <HeaderStyle BackColor="#aaaadd">
         </HeaderStyle>

         <AlternatingItemStyle BackColor="Gainsboro">
         </AlternatingItemStyle>

         <EditItemStyle BackColor="yellow">
         </EditItemStyle>

         <HeaderTemplate>

            Items

         </HeaderTemplate>
         
         <ItemTemplate>

            Item:
            <%# DataBinder.Eval(Container.DataItem, "Item") %> 

            <br>

            Quantity:
            <%# DataBinder.Eval(Container.DataItem, "Qty") %>

            <br>

            Price:
            <%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}") %>

            <br>

            <asp:LinkButton id="EditButton" 
                 Text="Edit" 
                 CommandName="Edit"
                 runat="server"/>

         </ItemTemplate>
              
         <EditItemTemplate>

            Item:
            <asp:Label id="ItemLabel" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Item") %>' 
                 runat="server"/>

            <br>

            Quantity:
            <asp:TextBox id="QtyTextBox" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Qty") %>' 
                 runat="server"/>

            <br>

            Price:
            <asp:TextBox id="PriceTextBox" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}") %>' 
                 runat="server"/>

            <br>

            <asp:LinkButton id="UpdateButton" 
                 Text="Update" 
                 CommandName="Update" 
                 runat="server"/>

            <asp:LinkButton id="DeleteButton" 
                 Text="Delete" 
                 CommandName="Delete" 
                 runat="server"/>

            <asp:LinkButton id="CancelButton" 
                 Text="Cancel" 
                 CommandName="Cancel" 
                 runat="server"/>

         </EditItemTemplate>

      </asp:DataList>

   </form>

</body>
</html>


[C#] 

<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>

<html>
<head>

   <script runat="server">

      // The Cart and CartView objects temporarily store the data source
      // for the DataList control while the page is being processed.
      DataTable Cart = new DataTable();
      DataView CartView;   
 
      void Page_Load(Object sender, EventArgs e) 
      {
 
         // With a database, use an select query to retrieve the data. 
         // Because the data source in this example is an in-memory
         // DataTable, retrieve the data from session state if it exists;
         // otherwise, create the data source.
         GetSource();

         // The DataList control maintains state between posts to the server;
         // it only needs to be bound to a data source the first time the
         // page is loaded or when the data source is updated.
         if (!IsPostBack)
         {

            BindList();

         }

         // Manually register the event-handling methods.
         ItemsList.EditCommand += 
             new DataListCommandEventHandler(this.Edit_Command);
         ItemsList.UpdateCommand += 
             new DataListCommandEventHandler(this.Update_Command);
         ItemsList.DeleteCommand += 
             new DataListCommandEventHandler(this.Delete_Command);
         ItemsList.CancelCommand += 
             new DataListCommandEventHandler(this.Cancel_Command);
                   
      }

      void BindList() 
      {

         // Set the data source and bind to the DataList control.
         ItemsList.DataSource = CartView;
         ItemsList.DataBind();

      }

      void GetSource()
      {

         // For this example, the data source is a DataTable that 
         // is stored in session state. If the data source does not exist,
         // create it; otherwise, load the data.
         if (Session["ShoppingCart"] == null) 
         {     

            // Create the sample data.
            DataRow dr;  
 
            // Define the columns of the table.
            Cart.Columns.Add(new DataColumn("Qty", typeof(Int32)));
            Cart.Columns.Add(new DataColumn("Item", typeof(String)));
            Cart.Columns.Add(new DataColumn("Price", typeof(Double)));

            // Store the table in session state to persist its values
            // between posts to the server.
            Session["ShoppingCart"] = Cart;
             
            // Populate the DataTable with sample data.
            for (int i = 1; i <= 9; i++) 
            {
               dr = Cart.NewRow();
               if (i % 2 != 0)
               {
                  dr[0] = 2;
               }
               else
               {
                  dr[0] = 1;
               }
               dr[1] = "Item " + i.ToString();
               dr[2] = (1.23 * (i + 1));
               Cart.Rows.Add(dr);
            }

         } 

         else
         {

            // Retrieve the sample data from session state.
            Cart = (DataTable)Session["ShoppingCart"];

         }         
 
         // Create a DataView and specify the field to sort by.
         CartView = new DataView(Cart);
         CartView.Sort="Item";

         return;

      }

      void Edit_Command(Object sender, DataListCommandEventArgs e) 
      {

         // Set the EditItemIndex property to the index of the item clicked
         // in the DataList control to enable editing for that item. Be sure
         // to rebind the DataList to the data source to refresh the control.
         ItemsList.EditItemIndex = e.Item.ItemIndex;
         BindList();

      }

      void Cancel_Command(Object sender, DataListCommandEventArgs e) 
      {

         // Set the EditItemIndex property to -1 to exit editing mode. Be sure
         // to rebind the DataList to the data source to refresh the control.
         ItemsList.EditItemIndex = -1;
         BindList();

      }

      void Delete_Command(Object sender, DataListCommandEventArgs e) 
      { 

         // Retrieve the name of the item to remove.
         String item = ((Label)e.Item.FindControl("ItemLabel")).Text;

         // Filter the CartView for the selected item and remove it from
         // the data source.
         CartView.RowFilter = "Item='" + item + "'";
         if (CartView.Count > 0) 
         {
            CartView.Delete(0);
         }
         CartView.RowFilter = "";

         // Set the EditItemIndex property to -1 to exit editing mode. Be sure
         // to rebind the DataList to the data source to refresh the control.
         ItemsList.EditItemIndex = -1;
         BindList();

      }

      void Update_Command(Object sender, DataListCommandEventArgs e) 
      {

         // Retrieve the updated values from the selected item.
         String item = ((Label)e.Item.FindControl("ItemLabel")).Text;
         String qty = ((TextBox)e.Item.FindControl("QtyTextBox")).Text;
         String price = ((TextBox)e.Item.FindControl("PriceTextBox")).Text;

         // With a database, use an update command to update the data.
         // Because the data source in this example is an in-memory 
         // DataTable, delete the old row and replace it with a new one.

         // Filter the CartView for the selected item and remove it from
         // the data source.
         CartView.RowFilter = "Item='" + item + "'";
         if (CartView.Count > 0)
         {
            CartView.Delete(0);
         }
         CartView.RowFilter = "";

         // ***************************************************************
         // Insert data validation code here. Make sure to validate the
         // values entered by the user before converting to the appropriate
         // data types and updating the data source.
         // ***************************************************************

         // Add a new entry to replace the previous item.
         DataRow dr = Cart.NewRow();
         dr[0] = qty;
         dr[1] = item;
         // If necessary, remove the '$' character from the price before
         // converting the price to a Double.
         if(price[0] == '$')
         {
            dr[2] = Convert.ToDouble(price.Substring(1));
         }
         else
         {
            dr[2] = Convert.ToDouble(price);
         }
         Cart.Rows.Add(dr);

         // Set the EditItemIndex property to -1 to exit editing mode. 
         // Be sure to rebind the DataList to the data source to refresh
         // the control.
         ItemsList.EditItemIndex = -1;
         BindList();

      }

   </script>

</head>
<body>

   <form runat=server>

      <h3>DataList Edit Example</h3>

      Click <b>Edit</b> to edit the values of the item.

      <br><br>
       
      <asp:DataList id="ItemsList"
           GridLines="Both"
           RepeatColumns="3"
           RepeatDirection="Horizontal"
           CellPadding="3"
           CellSpacing="0"
           runat="server">

         <HeaderStyle BackColor="#aaaadd">
         </HeaderStyle>

         <AlternatingItemStyle BackColor="Gainsboro">
         </AlternatingItemStyle>

         <EditItemStyle BackColor="yellow">
         </EditItemStyle>

         <HeaderTemplate>

            Items

         </HeaderTemplate>
         
         <ItemTemplate>

            Item:
            <%# DataBinder.Eval(Container.DataItem, "Item") %> 

            <br>

            Quantity:
            <%# DataBinder.Eval(Container.DataItem, "Qty") %>

            <br>

            Price:
            <%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}") %>

            <br>

            <asp:LinkButton id="EditButton" 
                 Text="Edit" 
                 CommandName="Edit"
                 runat="server"/>

         </ItemTemplate>
              
         <EditItemTemplate>

            Item:
            <asp:Label id="ItemLabel" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Item") %>' 
                 runat="server"/>

            <br>

            Quantity:
            <asp:TextBox id="QtyTextBox" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Qty") %>' 
                 runat="server"/>

            <br>

            Price:
            <asp:TextBox id="PriceTextBox" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}") %>' 
                 runat="server"/>

            <br>

            <asp:LinkButton id="UpdateButton" 
                 Text="Update" 
                 CommandName="Update" 
                 runat="server"/>

            <asp:LinkButton id="DeleteButton" 
                 Text="Delete" 
                 CommandName="Delete" 
                 runat="server"/>

            <asp:LinkButton id="CancelButton" 
                 Text="Cancel" 
                 CommandName="Cancel" 
                 runat="server"/>

         </EditItemTemplate>

      </asp:DataList>

   </form>

</body>
</html>

[C++, JScript] No example is available for C++ or JScript. To view a Visual Basic or C# example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Namespace: System.Web.UI.WebControls

Platforms: Windows 2000, Windows XP Professional, Windows Server 2003 family

Assembly: System.Web (in System.Web.dll)

See Also

DataListCommandEventArgs Members | System.Web.UI.WebControls Namespace | DataListCommandEventHandler | DataList | CancelCommand | DeleteCommand | EditCommand | ItemCommand | UpdateCommand

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