GridViewUpdatedEventArgs.Exception Property

Reference

Definition

Namespace:: System.Web.UI.WebControls

Assembly:: System.Web.dll

Important

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Gets the exception (if any) that was raised during the update operation.

public:
 property Exception ^ Exception { Exception ^ get(); };

public Exception Exception { get; }

member this.Exception : Exception

Public ReadOnly Property Exception As Exception

Property Value

Exception

The exception that was raised during the update operation. If no exceptions were raised, this property returns null.

Examples

The following example shows how to determine whether an exception occurred during an update operation.


<%@ 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_RowUpdated(Object sender, GridViewUpdatedEventArgs e)
  {
    // Use the Exception property to determine whether an exception
    // occurred during the update operation.
    if (e.Exception == null)
    {
      // Sometimes an error might occur that does not raise an 
      // exception, but prevents the update operation from 
      // completing. Use the AffectedRows property to determine 
      // whether the record was actually updated. 
      if (e.AffectedRows == 1)
      {
        // Use the Keys property to get the value of the key field.
        String keyFieldValue = e.Keys["CustomerID"].ToString();

        // Display a confirmation message.
        Message.Text = "Record " + keyFieldValue +
          " updated successfully. ";

        // Display the new and original values.
        DisplayValues((OrderedDictionary)e.NewValues, (OrderedDictionary)e.OldValues);
      }
      else
      {
        // Display an error message.
        Message.Text = "An error occurred during the update operation.";

        // When an error occurs, keep the GridView
        // control in edit mode.
        e.KeepInEditMode = true;
      }
    }
    else
    {
      // Insert the code to handle the exception.
      Message.Text = e.Exception.Message;

      // Use the ExceptionHandled property to indicate that the 
      // exception is already handled.
      e.ExceptionHandled = true;

      e.KeepInEditMode = true;
    }
  }

  void DisplayValues(OrderedDictionary newValues, OrderedDictionary oldValues)
  {

    Message.Text += "<br/></br>";

    // Iterate through the new and old values. Display the
    // values on the page.
    for (int i = 0; i < oldValues.Count; i++)
    {
      Message.Text += "Old Value=" + oldValues[i].ToString() +
        ", New Value=" + newValues[i].ToString() + "<br/>";
    }

    Message.Text += "</br>";

  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewUpdatedEventArgs Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridViewUpdatedEventArgs Example</h3>
            
      <!-- 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"
        onrowupdated="CustomersGridView_RowUpdated" 
        runat="server">
      </asp:gridview>
      
      <br/>
      
      <asp:label id="Message"
        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="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_RowUpdated(sender As Object, e As GridViewUpdatedEventArgs)
  
    ' Use the Exception property to determine whether an exception
    ' occurred during the update operation.
    If e.Exception Is Nothing Then
    
      ' Sometimes an error might occur that does not raise an 
      ' exception, but prevents the update operation from 
      ' completing. Use the AffectedRows property to determine 
      ' whether the record was actually updated. 
      If e.AffectedRows = 1 Then
      
        ' Use the Keys property to get the value of the key field.
        Dim keyFieldValue As String = e.Keys("CustomerID").ToString()

        ' Display a confirmation message.
        Message.Text = "Record " & keyFieldValue & _
          " updated successfully. "

        ' Display the new and original values.
        DisplayValues(CType(e.NewValues, OrderedDictionary), CType(e.OldValues, OrderedDictionary))

      Else
      
        ' Display an error message.
        Message.Text = "An error occurred during the update operation."

        ' When an error occurs, keep the GridView
        ' control in edit mode.
        e.KeepInEditMode = True
        
      End If
    
    Else
    
      ' Insert the code to handle the exception.
      Message.Text = e.Exception.Message

      ' Use the ExceptionHandled property to indicate that the 
      ' exception is already handled.
      e.ExceptionHandled = True

      e.KeepInEditMode = True
    
    End If
  
  End Sub

  Sub DisplayValues(ByVal newValues As OrderedDictionary, ByVal oldValues As OrderedDictionary)

    Message.Text &= "<br/></br>"

    ' Iterate through the new and old values. Display the
    ' values on the page.
    Dim i As Integer
    For i = 0 To oldValues.Count - 1
    
      Message.Text &= "Old Value=" & oldValues(i).ToString() & _
        ", New Value=" & newValues(i).ToString() & "<br/>"
    Next

    Message.Text &= "</br>"

  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewUpdatedEventArgs Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridViewUpdatedEventArgs Example</h3>
            
      <!-- 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"
        onrowupdated="CustomersGridView_RowUpdated" 
        runat="server">
      </asp:gridview>
      
      <br/>
      
      <asp:label id="Message"
        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="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

If an exception was raised and you decide to handle the exception in the event handler, set the ExceptionHandled property to true. Otherwise, the exception is thrown again by the GridView control.

Applies to

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