DetailsViewUpdatedEventArgs.Exception Vlastnost

Reference

Definice

Obor názvů:: System.Web.UI.WebControls

Sestavení:: System.Web.dll

Důležité

Některé informace platí pro předběžně vydaný produkt, který se může zásadně změnit, než ho výrobce nebo autor vydá. Microsoft neposkytuje žádné záruky, výslovné ani předpokládané, týkající se zde uváděných informací.

Získá výjimku (pokud existuje), která byla vyvolána během operace aktualizace.

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

public Exception Exception { get; }

member this.Exception : Exception

Public ReadOnly Property Exception As Exception

Hodnota vlastnosti

Exception

Představuje Exception výjimku, která byla vyvolána během operace aktualizace.

Příklady

Následující příklad kódu ukazuje, jak použít Exception vlastnost k určení, zda došlo k výjimce během operace aktualizace.


<%@ 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 CustomerDetailsView_ItemUpdated(Object sender, 
    DetailsViewUpdatedEventArgs e)
  {
    // Use the Exception property to determine whether an exception
    // occurred during the insert operation.
    if (e.Exception == null)
    {
      // Use the Values property to get the value entered by 
      // the user for the CompanyName field.
      String keyFieldValue = e.Keys["CustomerID"].ToString();

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

      // Display the old and new values.
      DisplayValues(e);

      if (e.AffectedRows == 1)
      {
        MessageLabel.Text += e.AffectedRows.ToString() + 
          " record updated.";
      }
      else
      {
        MessageLabel.Text += e.AffectedRows.ToString() + 
          " records updated.";
      }
    }
    else
    {
      // Insert the code to handle the exception.
      MessageLabel.Text = e.Exception.Message;

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

      // When an exception occurs, keep the DetailsView
      // control in edit mode.
      e.KeepInEditMode = true;
    }
  }

  void DisplayValues(DetailsViewUpdatedEventArgs e)
  {
    
    MessageLabel.Text += "<br/></br>";
    
    // Iterate through the OldValue and NewValues
    // properties and display the values.
    for (int i = 0; i < e.OldValues.Count; i++)
    {
      MessageLabel.Text += "Old Value=" + e.OldValues[i].ToString() +
        ", New Value=" + e.NewValues[i].ToString() + "<br/>";
    }

    MessageLabel.Text += "</br>";
    
  }
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >

  <head runat="server">
    <title>DetailsViewUpdatedEventArgs Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DetailsViewUpdatedEventArgs Example</h3>
                       
        <asp:detailsview id="CustomerDetailsView"
          datasourceid="DetailsViewSource"
          autogeneraterows="true"
          autogenerateeditbutton="true"  
          allowpaging="true"
          datakeynames="CustomerID" 
          onitemupdated="CustomerDetailsView_ItemUpdated"
          runat="server">
            
          <pagersettings position="Bottom"/> 
                    
        </asp:detailsview>
        
        <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="DetailsViewSource"
          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"/>
            
      </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 CustomerDetailsView_ItemUpdated(ByVal sender As Object, ByVal e As DetailsViewUpdatedEventArgs)
  
    ' Use the Exception property to determine whether an exception
    ' occurred during the insert operation.
    If e.Exception Is Nothing Then
    
      ' Use the Values property to get the value entered by 
      ' the user for the CompanyName field.
      Dim keyFieldValue As String = e.Keys("CustomerID").ToString()

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

      ' Display the old and new values.
      DisplayValues(e)

      If e.AffectedRows = 1 Then

        MessageLabel.Text &= e.AffectedRows.ToString() & _
          " record updated."
      
      Else
      
        MessageLabel.Text &= e.AffectedRows.ToString() & _
          " records updated."
      
      End If
    
    Else
    
      ' Insert the code to handle the exception.
      MessageLabel.Text = e.Exception.Message

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

      ' When an exception occurs, keep the DetailsView
      ' control in edit mode.
      e.KeepInEditMode = True
    
    End If
    
  End Sub

  Sub DisplayValues(ByVal e As DetailsViewUpdatedEventArgs)
    
    MessageLabel.Text &= "<br/></br>"
    
    ' Iterate through the OldValue and NewValues
    ' properties and display the values.
    Dim i As Integer
        
    For i = 0 To e.OldValues.Count - 1
    
      MessageLabel.Text &= "Old Value=" & e.OldValues(i).ToString() & _
        ", New Value=" & e.NewValues(i).ToString() & "<br/>"
    
    Next

    MessageLabel.Text &= "</br>"
    
  End Sub
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >

  <head runat="server">
    <title>DetailsViewUpdatedEventArgs Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DetailsViewUpdatedEventArgs Example</h3>
                       
        <asp:detailsview id="CustomerDetailsView"
          datasourceid="DetailsViewSource"
          autogeneraterows="true"
          autogenerateeditbutton="true"  
          allowpaging="true"
          datakeynames="CustomerID" 
          onitemupdated="CustomerDetailsView_ItemUpdated"
          runat="server">
            
          <pagersettings position="Bottom"/> 
                    
        </asp:detailsview>
        
        <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="DetailsViewSource"
          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"/>
            
      </form>
  </body>
</html>

Poznámky

Exception Pomocí vlastnosti určete výjimku (pokud existuje), která byla vyvolána během operace aktualizace. Pokud nebyly vyvolány žádné výjimky, vrátí nulltato vlastnost .

Poznámka

Pokud byla vyvolána výjimka a rozhodnete se ji zpracovat v obslužné rutině události, nezapomeňte nastavit ExceptionHandled vlastnost na true. V opačném případě se výjimka předá další metodě v zásobníku volání pro zpracování.

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