DataGrid.Columns Propriété
Définition
Important
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Obtient une collection d'objets représentant les colonnes du contrôle DataGrid.
public:
virtual property System::Web::UI::WebControls::DataGridColumnCollection ^ Columns { System::Web::UI::WebControls::DataGridColumnCollection ^ get(); };[System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)]
public virtual System.Web.UI.WebControls.DataGridColumnCollection Columns { get; }[<System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)>]
member this.Columns : System.Web.UI.WebControls.DataGridColumnCollectionPublic Overridable ReadOnly Property Columns As DataGridColumnCollectionValeur de propriété
Objet DataGridColumnCollection qui contient une collection d'objets représentant les colonnes du contrôle DataGrid.
- Attributs
Exemples
L’exemple de code suivant montre comment utiliser la Columns collection pour ajouter dynamiquement une colonne au DataGrid contrôle.
<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<script language="C#" runat="server">
DataTable Cart;
DataView CartView;
ICollection CreateDataSource()
{
DataTable dt = new DataTable();
DataRow dr;
dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
dt.Columns.Add(new DataColumn("StringValue", typeof(string)));
dt.Columns.Add(new DataColumn("CurrencyValue", typeof(double)));
for (int i = 0; i < 9; i++)
{
dr = dt.NewRow();
dr[0] = i;
dr[1] = "Item " + i.ToString();
dr[2] = 1.23 * (i + 1);
dt.Rows.Add(dr);
}
DataView dv = new DataView(dt);
return dv;
}
void Page_Load(Object sender, EventArgs e)
{
if (Session["DG4_ShoppingCart"] == null)
{
Cart = new DataTable();
Cart.Columns.Add(new DataColumn("Item", typeof(string)));
Cart.Columns.Add(new DataColumn("Price", typeof(string)));
Session["DG4_ShoppingCart"] = Cart;
}
else
{
Cart = (DataTable)Session["DG4_ShoppingCart"];
}
CartView = new DataView(Cart);
ShoppingCart.DataSource = CartView;
ShoppingCart.DataBind();
if (!IsPostBack)
{
// Load this data only once.
ItemsGrid.DataSource= CreateDataSource();
ItemsGrid.DataBind();
}
}
void Page_Init(Object sender, EventArgs e)
{
// Create a dynamic column to add to Columns collection.
BoundColumn NumberColumn = new BoundColumn();
NumberColumn.HeaderText="Item Number";
NumberColumn.DataField="IntegerValue";
// Add column to Columns collection.
ItemsGrid.Columns.AddAt(2, NumberColumn);
}
void Grid_CartCommand(Object sender, DataGridCommandEventArgs e) {
DataRow dr = Cart.NewRow();
// e.Item is the table row where the command is raised.
// For bound columns, the value is stored in the Text property of the TableCell.
TableCell itemCell = e.Item.Cells[2];
TableCell priceCell = e.Item.Cells[3];
string item = itemCell.Text;
string price = priceCell.Text;
if (((Button)e.CommandSource).CommandName == "AddToCart")
{
dr[0] = item;
dr[1] = price;
Cart.Rows.Add(dr);
}
else
{
//Remove from Cart.
CartView.RowFilter = "Item='" + item + "'";
if (CartView.Count > 0)
{
CartView.Delete(0);
}
CartView.RowFilter = "";
}
ShoppingCart.DataBind();
}
</script>
<head runat="server">
<title>DataGrid Columns Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DataGrid Columns Example</h3>
<table cellpadding="5">
<tr valign="top">
<td>
<b>Product List</b>
<asp:DataGrid id="ItemsGrid"
BorderColor="black"
BorderWidth="1"
CellPadding="3"
AutoGenerateColumns="false"
OnItemCommand="Grid_CartCommand"
runat="server">
<HeaderStyle BackColor="#00aaaa">
</HeaderStyle>
<Columns>
<asp:ButtonColumn
HeaderText="Add to cart"
ButtonType="PushButton"
Text="Add"
CommandName="AddToCart"/>
<asp:ButtonColumn
HeaderText="Remove from cart"
ButtonType="PushButton"
Text="Remove"
CommandName="RemoveFromCart"/>
<asp:BoundColumn
HeaderText="Item"
DataField="StringValue"/>
<asp:BoundColumn
HeaderText="Price"
DataField="CurrencyValue"
DataFormatString="{0:c}">
<ItemStyle HorizontalAlign="right">
</ItemStyle>
</asp:BoundColumn>
</Columns>
</asp:DataGrid>
</td>
<td>
<b>Shopping Cart</b>
<asp:DataGrid id="ShoppingCart"
runat="server"
BorderColor="black"
BorderWidth="1"
GridLines="Both"
ShowFooter="false"
CellPadding="3"
CellSpacing="0">
<HeaderStyle BackColor="#00aaaa">
</HeaderStyle>
</asp:DataGrid>
</td>
</tr>
</table>
</form>
</body>
</html>
<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<script language="VB" runat="server">
Dim Cart As DataTable
Dim CartView As DataView
Function CreateDataSource() As ICollection
Dim dt As New DataTable()
Dim dr As DataRow
dt.Columns.Add(New DataColumn("IntegerValue", GetType(Int32)))
dt.Columns.Add(New DataColumn("StringValue", GetType(String)))
dt.Columns.Add(New DataColumn("CurrencyValue", GetType(Double)))
Dim i As Integer
For i = 0 To 8
dr = dt.NewRow()
dr(0) = i
dr(1) = "Item " & i.ToString()
dr(2) = 1.23 *(i + 1)
dt.Rows.Add(dr)
Next i
Dim dv As New DataView(dt)
Return dv
End Function 'CreateDataSource
Sub Page_Load(sender As Object, e As EventArgs)
If Session("DG4_ShoppingCart") Is Nothing Then
Cart = New DataTable()
Cart.Columns.Add(New DataColumn("Item", GetType(String)))
Cart.Columns.Add(New DataColumn("Price", GetType(String)))
Session("DG4_ShoppingCart") = Cart
Else
Cart = CType(Session("DG4_ShoppingCart"), DataTable)
End If
CartView = New DataView(Cart)
ShoppingCart.DataSource = CartView
ShoppingCart.DataBind()
If Not IsPostBack Then
' Load this data only once.
ItemsGrid.DataSource = CreateDataSource()
ItemsGrid.DataBind()
End If
End Sub 'Page_Load
Sub Page_Init(sender As Object, e As EventArgs)
' Create a dynamic column to add to Columns collection.
Dim NumberColumn As New BoundColumn()
NumberColumn.HeaderText = "Item Number"
NumberColumn.DataField = "IntegerValue"
' Add column to Columns collection.
ItemsGrid.Columns.AddAt(2, NumberColumn)
End Sub 'Page_Init
Sub Grid_CartCommand(sender As Object, e As DataGridCommandEventArgs)
Dim dr As DataRow = Cart.NewRow()
' e.Item is the table row where the command is raised.
' For bound columns, the value is stored in the Text property of the TableCell.
Dim itemCell As TableCell = e.Item.Cells(2)
Dim priceCell As TableCell = e.Item.Cells(3)
Dim item As String = itemCell.Text
Dim price As String = priceCell.Text
If CType(e.CommandSource, Button).CommandName = "AddToCart" Then
dr(0) = item
dr(1) = price
Cart.Rows.Add(dr)
Else
'Remove from Cart.
CartView.RowFilter = "Item='" & item & "'"
If CartView.Count > 0 Then
CartView.Delete(0)
End If
CartView.RowFilter = ""
End If
ShoppingCart.DataBind()
End Sub 'Grid_CartCommand
</script>
<head runat="server">
<title>DataGrid Columns Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DataGrid Columns Example</h3>
<table cellpadding="5">
<tr valign="top">
<td>
<b>Product List</b>
<asp:DataGrid id="ItemsGrid"
BorderColor="black"
BorderWidth="1"
CellPadding="3"
AutoGenerateColumns="false"
OnItemCommand="Grid_CartCommand"
runat="server">
<HeaderStyle BackColor="#00aaaa">
</HeaderStyle>
<Columns>
<asp:ButtonColumn
HeaderText="Add to cart"
ButtonType="PushButton"
Text="Add"
CommandName="AddToCart"/>
<asp:ButtonColumn
HeaderText="Remove from cart"
ButtonType="PushButton"
Text="Remove"
CommandName="RemoveFromCart"/>
<asp:BoundColumn
HeaderText="Item"
DataField="StringValue"/>
<asp:BoundColumn
HeaderText="Price"
DataField="CurrencyValue"
DataFormatString="{0:c}">
<ItemStyle HorizontalAlign="right">
</ItemStyle>
</asp:BoundColumn>
</Columns>
</asp:DataGrid>
</td>
<td>
<b>Shopping Cart</b>
<asp:DataGrid id="ShoppingCart"
runat="server"
BorderColor="black"
BorderWidth="1"
GridLines="Both"
ShowFooter="false"
CellPadding="3"
CellSpacing="0">
<HeaderStyle BackColor="#00aaaa">
</HeaderStyle>
</asp:DataGrid>
</td>
</tr>
</table>
</form>
</body>
</html>
<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<script runat="server">
ICollection CreateDataSource()
{
// Create sample data for the DataGrid control.
DataTable dt = new DataTable();
DataRow dr;
// Define the columns of the table.
dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
dt.Columns.Add(new DataColumn("StringValue", typeof(string)));
dt.Columns.Add(new DataColumn("CurrencyValue", typeof(double)));
// Populate the table with sample values.
for (int i = 0; i < 5; i++)
{
dr = dt.NewRow();
dr[0] = i;
dr[1] = "Item " + i.ToString();
dr[2] = 1.23 * (i + 1);
dt.Rows.Add(dr);
}
DataView dv = new DataView(dt);
return dv;
}
void Page_Load(Object sender, EventArgs e)
{
// Load sample data only once, when the page is first loaded.
if (!IsPostBack)
{
ItemsGrid.DataSource = CreateDataSource();
ItemsGrid.DataBind();
}
}
void Button_Click(Object sender, EventArgs e)
{
// Count the number of selected items in the DataGrid control.
int count = 0;
// Display the selected times.
Message.Text = "You Selected: <br />";
// Iterate through each item (row) in the DataGrid control and
// determine whether it is selected.
foreach (DataGridItem item in ItemsGrid.Items)
{
DetermineSelection(item, ref count);
}
// If no items are selected, display the appropriate message.
if (count == 0)
{
Message.Text = "No items selected";
}
}
void DetermineSelection(DataGridItem item, ref int count)
{
// Retrieve the SelectCheckBox CheckBox control from the
// specified item (row) in the DataGrid control.
CheckBox selection = (CheckBox)item.FindControl("SelectCheckBox");
// If the item is selected, display the appropriate message and
// increment the count of selected items.
if (selection != null)
{
if (selection.Checked)
{
Message.Text += "- " + item.Cells[1].Text + "<br />";
count++;
}
}
}
void Check_Change(Object sender, EventArgs e)
{
// Show or hide the first column depending on the value of
// the check box.
if (ShowCheckBox.Checked)
{
ItemsGrid.Columns[0].Visible = true;
}
else
{
ItemsGrid.Columns[0].Visible = false;
}
}
</script>
<head runat="server">
<title>DataGridColumn Visible Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DataGridColumn Visible Example</h3>
Select whether to show or hide the first column.
<br /><br />
<b>Product List</b>
<asp:DataGrid id="ItemsGrid"
BorderColor="black"
BorderWidth="1"
CellPadding="3"
ShowFooter="True"
AutoGenerateColumns="False"
runat="server">
<HeaderStyle BackColor="#00aaaa">
</HeaderStyle>
<FooterStyle BackColor="#00aaaa">
</FooterStyle>
<Columns>
<asp:BoundColumn DataField="IntegerValue"
Visible="True"
HeaderText="Item"/>
<asp:BoundColumn DataField="StringValue"
Visible="True"
HeaderText="Description"/>
<asp:BoundColumn DataField="CurrencyValue"
Visible="True"
HeaderText="Price"
DataFormatString="{0:c}">
<ItemStyle HorizontalAlign="Right">
</ItemStyle>
</asp:BoundColumn>
<asp:TemplateColumn HeaderText="Select Item"
Visible="True" >
<ItemTemplate>
<asp:CheckBox id="SelectCheckBox"
Text="Add to Cart"
Checked="False"
runat="server"/>
</ItemTemplate>
</asp:TemplateColumn>
</Columns>
</asp:DataGrid>
<br /><br />
<asp:Button id="SubmitButton"
Text="Submit"
OnClick = "Button_Click"
runat="server"/>
<br /><br />
<asp:Label id="Message"
runat="server"/>
<hr />
<asp:CheckBox id="ShowCheckBox"
Text="Show first column"
AutoPostBack="True"
OnCheckedChanged="Check_Change"
Checked="True"
runat="server"/>
</form>
</body>
</html>
<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<script runat="server">
Function CreateDataSource() As ICollection
' Create sample data for the DataGrid control.
Dim dt As DataTable = New DataTable()
Dim dr As DataRow
' Define the columns of the table.
dt.Columns.Add(New DataColumn("IntegerValue", GetType(Int32)))
dt.Columns.Add(New DataColumn("StringValue", GetType(string)))
dt.Columns.Add(New DataColumn("CurrencyValue", GetType(double)))
' Populate the table with sample values.
Dim i As Integer
For i = 0 to 4
dr = dt.NewRow()
dr(0) = i
dr(1) = "Item " & i.ToString()
dr(2) = 1.23 * (i + 1)
dt.Rows.Add(dr)
Next i
Dim dv As DataView = New DataView(dt)
Return dv
End Function
Sub Page_Load(sender As Object, e As EventArgs)
' Load sample data only once, when the page is first loaded.
If Not IsPostBack Then
ItemsGrid.DataSource = CreateDataSource()
ItemsGrid.DataBind()
End If
End Sub
Sub Button_Click(sender As Object, e As EventArgs)
' Count the number of selected items in the DataGrid control.
Dim count As Integer = 0
' Display the selected times.
Message.Text = "You Selected: <br />"
' Iterate through each item (row) in the DataGrid control and
' determine whether it is selected.
Dim item As DataGridItem
For Each item In ItemsGrid.Items
DetermineSelection(item, count)
Next
' If no items are selected, display the appropriate message.
If count = 0 Then
Message.Text = "No items selected"
End If
End Sub
Sub DetermineSelection(item As DataGridItem, ByRef count As Integer)
' Retrieve the SelectCheckBox CheckBox control from the
' specified item (row) in the DataGrid control.
Dim selection As CheckBox = _
CType(item.FindControl("SelectCheckBox"), CheckBox)
' If the item is selected, display the appropriate message and
' increment the count of selected items.
If Not selection Is Nothing Then
If selection.Checked Then
Message.Text &= "- " & item.Cells(1).Text & "<br />"
count = count + 1
End If
End If
End Sub
Sub Check_Change(sender As Object, e As EventArgs)
' Show or hide the first column depending on the value of
' the check box.
If ShowCheckBox.Checked Then
ItemsGrid.Columns(0).Visible = True
Else
ItemsGrid.Columns(0).Visible = False
End If
End Sub
</script>
<head runat="server">
<title>DataGridColumn Visible Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DataGridColumn Visible Example</h3>
Select whether to show or hide the first column.
<br /><br />
<b>Product List</b>
<asp:DataGrid id="ItemsGrid"
BorderColor="black"
BorderWidth="1"
CellPadding="3"
ShowFooter="True"
AutoGenerateColumns="False"
runat="server">
<HeaderStyle BackColor="#00aaaa">
</HeaderStyle>
<FooterStyle BackColor="#00aaaa">
</FooterStyle>
<Columns>
<asp:BoundColumn DataField="IntegerValue"
Visible="True"
HeaderText="Item"/>
<asp:BoundColumn DataField="StringValue"
Visible="True"
HeaderText="Description"/>
<asp:BoundColumn DataField="CurrencyValue"
Visible="True"
HeaderText="Price"
DataFormatString="{0:c}">
<ItemStyle HorizontalAlign="Right">
</ItemStyle>
</asp:BoundColumn>
<asp:TemplateColumn HeaderText="Select Item"
Visible="True" >
<ItemTemplate>
<asp:CheckBox id="SelectCheckBox"
Text="Add to Cart"
Checked="False"
runat="server"/>
</ItemTemplate>
</asp:TemplateColumn>
</Columns>
</asp:DataGrid>
<br /><br />
<asp:Button id="SubmitButton"
Text="Submit"
OnClick = "Button_Click"
runat="server"/>
<br /><br />
<asp:Label id="Message"
runat="server"/>
<hr />
<asp:CheckBox id="ShowCheckBox"
Text="Show first column"
AutoPostBack="True"
OnCheckedChanged="Check_Change"
Checked="True"
runat="server"/>
</form>
</body>
</html>
Remarques
Utilisez cette propriété pour contrôler par programmation la collection de colonnes dans le DataGrid contrôle. La Columns collection contient des colonnes déclarées explicitement qui sont rendues dans le DataGrid contrôle.
Notes
Les colonnes déclarées explicitement peuvent être utilisées conjointement avec des colonnes générées automatiquement. Lors de l’utilisation des deux, les colonnes déclarées explicitement sont rendues en premier, suivies des colonnes générées automatiquement. Les colonnes générées automatiquement ne sont pas ajoutées à la Columns collection.
L’ordre d’affichage des colonnes dans le DataGrid contrôle est contrôlé par l’ordre d’affichage des colonnes dans la Columns collection.
Le tableau suivant montre les différentes classes de colonnes qui dérivent de la DataGridColumn classe et peuvent être utilisées dans la Columns collection.
| Type de colonne | Description |
|---|---|
| BoundColumn | Affiche une colonne liée à un champ dans une source de données. Il affiche chaque élément du champ sous forme de texte. Il s’agit du type de colonne par défaut du DataGrid contrôle. |
| ButtonColumn | Affiche un bouton de commande pour chaque élément de la colonne. Cela vous permet de créer une colonne de contrôles de bouton personnalisés, tels que le Add bouton ou Remove . |
| EditCommandColumn | Affiche une colonne qui contient des commandes de modification pour chaque élément de la colonne. |
| HyperLinkColumn | Affiche le contenu de chaque élément de la colonne sous forme de lien hypertexte. Le contenu de la colonne peut être lié à un champ dans une source de données ou à un texte statique. |
| TemplateColumn | Affiche chaque élément de la colonne suivant un modèle spécifié. Cela vous permet de fournir des contrôles personnalisés dans la colonne. |
Notes
Bien que vous puissiez ajouter par programmation des colonnes à la Columns collection, il est plus facile de répertorier les colonnes de manière statique, puis d’utiliser la Visible propriété pour afficher ou masquer la colonne.
S’applique à
Voir aussi
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