GridViewEditEventHandler Delegate

Reference

Definition

Namespace:: System.Web.UI.WebControls

Assembly:: System.Web.dll

Important

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Represents the method that handles the RowEditing event of a GridView control.

public delegate void GridViewEditEventHandler(System::Object ^ sender, GridViewEditEventArgs ^ e);

public delegate void GridViewEditEventHandler(object sender, GridViewEditEventArgs e);

type GridViewEditEventHandler = delegate of obj * GridViewEditEventArgs -> unit

Public Delegate Sub GridViewEditEventHandler(sender As Object, e As GridViewEditEventArgs)

Parameters

sender: Object

The source of the event.

e: GridViewEditEventArgs

A GridViewEditEventArgs object that contains the event data.

Examples

The following example demonstrates how to programmatically add a GridViewEditEventHandler delegate to the RowEditing event of a GridView control.


<%@ Page language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

  void Page_Load(Object sender, EventArgs e)
  {
        
    // Create a new GridView control.
    GridView customersGridView = new GridView();

    // Set the GridView control's properties.
    customersGridView.ID = "CustomersGridView";
    customersGridView.DataSourceID = "CustomersSqlDataSource";
    customersGridView.AutoGenerateColumns = true;
    customersGridView.AutoGenerateEditButton = true;
    customersGridView.AllowPaging = true;
    customersGridView.DataKeyNames = new String[] { "CustomerID" };
      
    // Programmatically register the event-handling method.
    customersGridView.RowEditing += new GridViewEditEventHandler(this.CustomersGridView_RowEditing);
        
    // Add the GridView control to the Controls collection
    // of the PlaceHolder control.
    GridViewPlaceHolder.Controls.Add(customersGridView);
        
  }

  void CustomersGridView_RowEditing(Object sender, GridViewEditEventArgs e)
  {

    // User the sender parameter to retrieve the GridView control
    // that raised the event.
    GridView customersGridView = (GridView)sender;
    
    // Get the country for the row being edited. For this example, the
    // country is contained in the seventh column (index 6). 
    String country = customersGridView.Rows[e.NewEditIndex].Cells[6].Text;

    // For this example, cancel the edit operation if the user attempts
    // to edit the record of a customer from the USA. 
    if (country == "USA")
    {
      // Cancel the edit operation.
      e.Cancel = true;
      Message.Text = "You cannot edit this record.";
    }
    else
    {
      Message.Text = "";
    }
    
  }
    
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewEditEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridViewEditEventHandler Example</h3>
          
      <asp:label id="Message"
        forecolor="Red"
        runat="server"/>
                
      <br/>
            
      <asp:placeholder id="GridViewPlaceHolder"
        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="CustomersSqlDataSource"  
        selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
        updatecommand="Update Customers SET CompanyName=@CompanyName, Address=@Address, City=@City, PostalCode=@PostalCode, Country=@Country WHERE (CustomerID = @CustomerID)"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
        runat="server">
      </asp:sqldatasource>
            
    </form>
  </body>
</html>


<%@ 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 Page_Load(ByVal sender As Object, ByVal e As EventArgs)
        
    ' Create a new GridView control.
    Dim customersGridView As New GridView()

    ' Set the GridView control's properties.
    customersGridView.ID = "CustomersGridView"
    customersGridView.DataSourceID = "CustomersSqlDataSource"
    customersGridView.AutoGenerateColumns = True
    customersGridView.AutoGenerateEditButton = True
    customersGridView.AllowPaging = True
    Dim keyArray() As String = {"CustomerID"}
    customersGridView.DataKeyNames = keyArray
      
    ' Programmatically register the event-handling method.
    AddHandler customersGridView.RowEditing, AddressOf CustomersGridView_RowEditing
        
    ' Add the GridView control to the Controls collection
    ' of the PlaceHolder control.
    GridViewPlaceHolder.Controls.Add(customersGridView)
        
  End Sub

  Sub CustomersGridView_RowEditing(ByVal sender As Object, ByVal e As GridViewEditEventArgs)

    ' User the sender parameter to retrieve the GridView control
    ' that raised the event.
    Dim customersGridView As GridView = CType(sender, GridView)
    
    ' Get the country for the row being edited. For this example, the
    ' country is contained in the seventh column (index 6). 
    Dim country As String = customersGridView.Rows(e.NewEditIndex).Cells(6).Text

    ' For this example, cancel the edit operation if the user attempts
    ' to edit the record of a customer from the USA. 
    If country = "USA" Then
    
      ' Cancel the edit operation.
      e.Cancel = True
      Message.Text = "You cannot edit this record."
    
    Else
    
      Message.Text = ""
      
    End If
    
  End Sub
    
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewEditEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridViewEditEventHandler Example</h3>
          
      <asp:label id="Message"
        forecolor="Red"
        runat="server"/>
                
      <br/>
            
      <asp:placeholder id="GridViewPlaceHolder"
        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="CustomersSqlDataSource"  
        selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
        updatecommand="Update Customers SET CompanyName=@CompanyName, Address=@Address, City=@City, PostalCode=@PostalCode, Country=@Country WHERE (CustomerID = @CustomerID)"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
        runat="server">
      </asp:sqldatasource>
            
    </form>
  </body>
</html>

The following example demonstrates how to declaratively add a GridViewEditEventHandler delegate to the RowEditing event of a GridView control.


<%@ Page language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

  void CustomersGridView_RowEditing(Object sender, GridViewEditEventArgs e)
  {
    
    // Get the country for the row being edited. For this example, the
    // country is contained in the seventh column (index 6). 
    String country = CustomersGridView.Rows[e.NewEditIndex].Cells[6].Text;

    // For this example, cancel the edit operation if the user attempts
    // to edit the record of a customer from the Unites States. 
    if (country == "USA")
    {
      // Cancel the edit operation.
      e.Cancel = true;
      Message.Text = "You cannot edit this record.";
    }
    else
    {
      Message.Text = "";
    }
    
  }
    
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridView RowEditing Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridView RowEditing Example</h3>
          
      <asp:label id="Message"
        forecolor="Red"
        runat="server"/>
                
      <br/>
            
      <!-- The GridView control automatically sets the columns     -->
      <!-- specified in the datakeynames property as read-only.    -->
      <!-- No input controls are rendered for these columns in     -->
      <!-- edit mode.                                              -->
      <asp:gridview id="CustomersGridView" 
        datasourceid="CustomersSqlDataSource" 
        autogeneratecolumns="true"
        autogenerateeditbutton="true"
        allowpaging="true" 
        datakeynames="CustomerID"
        onrowediting="CustomersGridView_RowEditing"   
        runat="server">
      </asp:gridview>
            
      <!-- 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="CustomersSqlDataSource"  
        selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
        updatecommand="Update Customers SET CompanyName=@CompanyName, Address=@Address, City=@City, PostalCode=@PostalCode, Country=@Country WHERE (CustomerID = @CustomerID)"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
        runat="server">
      </asp:sqldatasource>
            
    </form>
  </body>
</html>


<%@ 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 CustomersGridView_RowEditing(ByVal sender As Object, ByVal e As GridViewEditEventArgs)
        
    ' Get the country for the row being edited. For this example, the
    ' country is contained in the seventh column (index 6). 
    Dim country As String = CustomersGridView.Rows(e.NewEditIndex).Cells(6).Text

    ' For this example, cancel the edit operation if the user attempts
    ' to edit the record of a customer from the United States. 
    If country = "USA" Then
    
      ' Cancel the edit operation.
      e.Cancel = True
      Message.Text = "You cannot edit this record."
     
    Else
      
      Message.Text = ""
      
    End If
    
  End Sub
    
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridView RowEditing Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridView RowEditing Example</h3>
          
      <asp:label id="Message"
        forecolor="Red"
        runat="server"/>
                
      <br/>
            
      <!-- The GridView control automatically sets the columns     -->
      <!-- specified in the datakeynames property as read-only.    -->
      <!-- No input controls are rendered for these columns in     -->
      <!-- edit mode.                                              -->
      <asp:gridview id="CustomersGridView" 
        datasourceid="CustomersSqlDataSource" 
        autogeneratecolumns="true"
        autogenerateeditbutton="true"
        allowpaging="true" 
        datakeynames="CustomerID"
        onrowediting="CustomersGridView_RowEditing"   
        runat="server">
      </asp:gridview>
            
      <!-- 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="CustomersSqlDataSource"  
        selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
        updatecommand="Update Customers SET CompanyName=@CompanyName, Address=@Address, City=@City, PostalCode=@PostalCode, Country=@Country WHERE (CustomerID = @CustomerID)"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
        runat="server">
      </asp:sqldatasource>
            
    </form>
  </body>
</html>

Remarks

The RowEditing event is raised when an Edit button (a button with its CommandName property set to "Edit") is clicked, but before the GridView control enters edit mode. This allows you to provide an event-handling method that performs a custom routine, such as canceling the edit operation, whenever this event occurs.

When you create a GridViewEditEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event-handler delegates, see Handling and Raising Events.

Extension Methods

GetMethodInfo(Delegate)

Gets an object that represents the method represented by the specified delegate.

Applies to

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