FormViewUpdateEventArgs.Keys Property
Gets a dictionary that contains the original key field name/value pairs for the record to update.
Assembly: System.Web (in System.Web.dll)
Property Value
Type: System.Collections.Specialized.IOrderedDictionaryAn IOrderedDictionary that contains a dictionary of the original key field name/value pairs for the record to update.
The Keys property contains the original values of the key fields listed in the DataKeyNames property of a FormView control. Use the Keys property to access the original values of the key fields for the record to update. For example, you can use these values to keep a log of updated records.
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If you allow the user to update the values of the key fields, the Keys property contains the original key field values. The updated values are stored in the NewValues property. |
The Keys property returns an OrderedDictionary object that implements the System.Collections.Specialized.IOrderedDictionary interface. The OrderedDictionary object contains System.Collections.DictionaryEntry objects that represent the fields of the updated record. To access the field names, use the Keys property of the OrderedDictionary object. Similarly, you can access the field values by using the Values property.
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As a shortcut, you can also use the indexer of the OrderedDictionary object to access the field values directly. Data source controls that rely on the field order (such as AccessDataSource) can access field values only by index. |
The following example demonstrates how to use the Keys property to access the value of the key field for the record being updated.
<%@ Page language="VB" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <script runat="server"> Sub EmployeeFormView_ItemUpdating(ByVal sender As Object, ByVal e As FormViewUpdateEventArgs) Handles EmployeeFormView.ItemUpdating ' Validate the field values entered by the user. This ' example determines whether the user left any fields ' empty. The names of the empty fields are added to ' an ArrayList object. ' Use the NewValues property to access the new ' values entered by the user. Dim emptyFieldList As ArrayList = ValidateFields(CType(e.NewValues, OrderedDictionary)) If emptyFieldList.Count > 0 Then ' The user left some fields empty. Display an error message. ' Use the Keys property to retrieve the key field value. Dim keyValue As String = e.Keys("EmployeeID").ToString() MessageLabel.Text = "You must enter a value for each field of record " & _ keyValue & ".<br/>The following fields are missing:<br/><br/>" ' Display the missing fields. Dim value As String For Each value In emptyFieldList ' Use the OldValues property access the original value ' of a field. MessageLabel.Text &= value & " - Original Value = " & _ e.OldValues(value).ToString() & "<br />" Next ' Cancel the update operation. e.Cancel = True Else ' The field values passed validation. Clear the ' error message label. MessageLabel.Text = "" End If End Sub Function ValidateFields(ByVal list As OrderedDictionary) As ArrayList ' Create an ArrayList object to store the ' names of any empty fields. Dim emptyFieldList As New ArrayList() ' Iterate though the field values entered by ' the user and check for an empty field. Dim entry As DictionaryEntry For Each entry In list If entry.Value.Equals("") Then ' Add the field name to the ArrayList object. emptyFieldList.Add(entry.Key.ToString()) End If Next Return emptyFieldList End Function Sub EmployeeFormView_ModeChanged(ByVal sender As Object, ByVal e As EventArgs) Handles EmployeeFormView.ModeChanged ' Clear the error message label. MessageLabel.Text = "" End Sub </script> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>FormViewUpdateEventArgs Example</title> </head> <body> <form id="form1" runat="server"> <h3>FormViewUpdateEventArgs Example</h3> <asp:formview id="EmployeeFormView" datasourceid="EmployeeSource" allowpaging="true" datakeynames="EmployeeID" emptydatatext="No employees found." runat="server"> <itemtemplate> <table> <tr> <td rowspan="6"> <asp:image id="EmployeeImage" imageurl='<%# Eval("PhotoPath") %>' alternatetext='<%# Eval("LastName") %>' runat="server"/> </td> <td colspan="2"> </td> </tr> <tr> <td> <b>Name:</b> </td> <td> <%# Eval("FirstName") %> <%# Eval("LastName") %> </td> </tr> <tr> <td> <b>Title:</b> </td> <td> <%# Eval("Title") %> </td> </tr> <tr style="height:150" valign="top"> <td> <b>Address:</b> </td> <td> <%# Eval("Address") %><br/> <%# Eval("City") %> <%# Eval("Region") %> <%# Eval("PostalCode") %><br/> <%# Eval("Country") %> </td> </tr> <tr> <td colspan="2"> <asp:linkbutton id="Edit" text="Edit" commandname="Edit" runat="server"/> </td> </tr> </table> </itemtemplate> <edititemtemplate> <table> <tr> <td rowspan="6"> <asp:image id="EmployeeEditImage" imageurl='<%# Eval("PhotoPath") %>' alternatetext='<%# Eval("LastName") %>' runat="server"/> </td> <td colspan="2"> </td> </tr> <tr> <td> <b><asp:Label runat="server" AssociatedControlID="FirstNameUpdateTextBox" Text="Name" />:</b> </td> <td> <asp:textbox id="FirstNameUpdateTextBox" text='<%# Bind("FirstName") %>' accesskey="n" tabindex="1" runat="server"/> <asp:textbox id="LastNameUpdateTextBox" text='<%# Bind("LastName") %>' accesskey="l" tabindex="2" runat="server"/> </td> </tr> <tr> <td> <b><asp:Label runat="server" AssociatedControlID="TitleUpdateTextBox" Text="Title" />:</b> </td> <td> <asp:textbox id="TitleUpdateTextBox" text='<%# Bind("Title") %>' accesskey="t" tabindex="3" runat="server"/> </td> </tr> <tr> <b><asp:Label runat="server" AssociatedControlID="HireDateUpdateTextBox" Text="Hire Date" />:</b> <td> <asp:textbox id="HireDateUpdateTextBox" text='<%# Bind("HireDate", "{0:d}") %>' accesskey="h" tabindex="4" runat="server" /> </td> </tr> <tr style="height:150" valign="top"> <td> <b><asp:Label runat="server" AssociatedControlID="AddressUpdateTextBox" Text="Address" />:</b> </td> <td> <asp:textbox id="AddressUpdateTextBox" text='<%# Bind("Address") %>' accesskey="a" tabindex="5" runat="server"/> <br/> <asp:textbox id="CityUpdateTextBox" text='<%# Bind("City") %>' accesskey="c" tabindex="6" runat="server"/> <asp:textbox id="RegionUpdateTextBox" text='<%# Bind("Region") %>' width="40" accesskey="r" tabindex="7" runat="server"/> <asp:textbox id="PostalCodeUpdateTextBox" text='<%# Bind("PostalCode") %>' width="60" accesskey="p" tabindex="8" runat="server"/> <br/> <asp:textbox id="CountryUpdateTextBox" text='<%# Bind("Country") %>' accesskey="u" tabindex="9" runat="server"/> </td> </tr> <tr> <td colspan="2"> <asp:linkbutton id="UpdateButton" text="Update" tabindex="10" commandname="Update" runat="server"/> <asp:linkbutton id="CancelButton" text="Cancel" tabindex="11" commandname="Cancel" runat="server"/> </td> </tr> </table> </edititemtemplate> </asp:formview> <br/><br/> <asp:label id="MessageLabel" forecolor="Red" runat="server"/> <!-- This example uses Microsoft SQL Server and connects --> <!-- to the Northwind sample database. Use an ASP.NET --> <!-- expression to retrieve the connection string value --> <!-- from the Web.config file. --> <asp:sqldatasource id="EmployeeSource" selectcommand="Select [EmployeeID], [LastName], [FirstName], [Title], [Address], [City], [Region], [PostalCode], [Country], [HireDate], [PhotoPath] From [Employees]" updatecommand="Update [Employees] Set [LastName]=@LastName, [FirstName]=@FirstName, [Title]=@Title, [Address]=@Address, [City]=@City, [Region]=@Region, [PostalCode]=@PostalCode, [Country]=@Country Where [EmployeeID]=@EmployeeID" connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" runat="server"/> </form> </body> </html>
Available since 2.0
FormView
FormViewUpdateEventHandler
System.Collections.Specialized.IOrderedDictionary
System.Collections.Specialized.OrderedDictionary
System.Collections.DictionaryEntry
OrderedDictionary.Keys
OrderedDictionary.Values
NewValues
OldValues
ItemUpdating
FormViewUpdateEventArgs Class
System.Web.UI.WebControls Namespace
