Auf Englisch lesen

Teilen über

FormViewInsertedEventHandler Delegat

  • Referenz

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Stellt die Methode dar, die das ItemInserted-Ereignis eines FormView-Steuerelements behandelt.

C# 
public delegate void FormViewInsertedEventHandler(object sender, FormViewInsertedEventArgs e);

Parameter

sender
Object

Die Quelle des Ereignisses.

e
FormViewInsertedEventArgs

Ein FormViewInsertedEventArgs, das die Ereignisdaten enthält.

Beispiele

Im folgenden Beispiel wird veranschaulicht, wie sie dem ItemInserted Ereignis eines Steuerelements programmgesteuert einen FormViewFormViewInsertedEventHandler Delegaten hinzufügen.

ASP.NET (C#) 

<%@ Page language="C#" %>
<%@ import namespace="System.Data"%>

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

  // To dynamically create a template for a FormView control,
  // you must create a custom template class to represent 
  // the template. This template class represents the item
  // template for a FormView control.
  private sealed class EmployeeItemTemplate : ITemplate
  {

    // When implementing the ITemplate interface, you must
    // implement the InstantiateIn method. The FormView
    // control calls this method to create the template's 
    // content. 
    void ITemplate.InstantiateIn(Control container)
    {
      // Create the child controls contained in the template.
      // For this example, the item template displays the
      // FirstName and LastName fields from the data source.
      // To support data binding, create event handlers 
      // for the DataBinding event of each child control.
      // The event handlers must bind the appropriate value 
      // to each control.
      Label firstNameLabel = new Label();
      firstNameLabel.ID = "FirstNameLabel";
      firstNameLabel.DataBinding += new EventHandler(FirstNameLabel_DataBinding);

      LiteralControl nameLineBreak = new LiteralControl("<br/>");
      LiteralControl buttonLineBreak = new LiteralControl("<br/>");

      Label lastNameLabel = new Label();
      lastNameLabel.ID = "LastNameLabel";
      lastNameLabel.DataBinding += new EventHandler(LastNameLabel_DataBinding);

      Button newButton = new Button();
      newButton.ID = "NewButton";
      newButton.CommandName = "New";
      newButton.Text = "New";

      // Add the controls to the Controls collection of the 
      // container control.
      container.Controls.Add(firstNameLabel);
      container.Controls.Add(nameLineBreak);
      container.Controls.Add(lastNameLabel);
      container.Controls.Add(buttonLineBreak);
      container.Controls.Add(newButton);

    }

    // This event handler binds the value of the FirstName field
    // to the FirstNameLabel Label control displayed in the template.
    private void FirstNameLabel_DataBinding(Object sender, EventArgs e)
    {
      // Use the sender parameter to retrieve the Label control
      // being bound to data.
      Label firstNameLabelControl = (Label)sender;

      // Retrieve the value to bind to the Label control. First,
      // use the NamingContainer property to retrieve the parent 
      // control of the Label control. In this example, the parent 
      // control is the FormView control.
      FormView formViewContainer = (FormView)firstNameLabelControl.NamingContainer;

      // Get the data item bound to the FormView control.
      DataRowView rowView = (DataRowView)formViewContainer.DataItem;

      // Use the data item to retrieve the value of the FirstName field.
      // Set the Text property of the Label control to this value.        
      firstNameLabelControl.Text = rowView["FirstName"].ToString();
    }

    // This event handler binds the value of the LastName field
    // to the LastNameLabel Label control displayed in the template.
    private void LastNameLabel_DataBinding(Object sender, EventArgs e)
    {
      // Use the sender parameter to retrieve the Label control
      // being bound to data.
      Label lastNameLabelControl = (Label)sender;

      // Retrieve the value to bind to the Label control. First,
      // use the NamingContainer property to retrieve the parent 
      // control of the Label control. In this example, the parent 
      // control is the FormView control.
      FormView formViewContainer = (FormView)lastNameLabelControl.NamingContainer;

      // Get the data item bound to the FormView control.
      DataRowView rowView = (DataRowView)formViewContainer.DataItem;

      // Use the data item to retrieve the value of the LastName field.
      // Set the Text property of the Label control to this value.         
      lastNameLabelControl.Text = rowView["LastName"].ToString();
    }

  }
  
  // This template class represents the insert item
  // template for a FormView control.
  private sealed class EmployeeInsertItemTemplate : ITemplate
  {

    void ITemplate.InstantiateIn(Control container)
    {
      // Create the child controls contained in the template.
      // The insert item template should contain the input 
      // controls for the user to enter a record.
      TextBox firstNameTextBox = new TextBox();
      firstNameTextBox.ID = "FirstNameTextBox";

      LiteralControl nameLineBreak = new LiteralControl("<br/>");
      LiteralControl buttonLineBreak = new LiteralControl("<br/>");

      TextBox lastNameTextBox = new TextBox();
      lastNameTextBox.ID = "LastNameTextBox";

      Button insertButton = new Button();
      insertButton.ID = "InsertButton";
      insertButton.CommandName = "Insert";
      insertButton.Text = "Insert";

      Button cancelButton = new Button();
      cancelButton.ID = "CancelButton";
      cancelButton.CommandName = "Cancel";
      cancelButton.Text = "Cancel";

      // Add the controls to the Controls collection of the 
      // container control.
      container.Controls.Add(firstNameTextBox);
      container.Controls.Add(nameLineBreak);
      container.Controls.Add(lastNameTextBox);
      container.Controls.Add(buttonLineBreak);
      container.Controls.Add(insertButton);
      container.Controls.Add(cancelButton);

    }
  }

  void Page_Load(Object sender, EventArgs e)
  {

    // Create a new FormView object.
    FormView employeesFormView = new FormView();

    // Set the FormView object's properties.
    employeesFormView.ID = "EmployeesFormView";
    employeesFormView.DataSourceID = "EmployeeSource";
    employeesFormView.AllowPaging = true;
    employeesFormView.HeaderText = "Employee Name";
    employeesFormView.DataKeyNames = new String[1] { "EmployeeID" };

    // Programmatically register the event handlers for the 
    // the FormView control.
    employeesFormView.ItemInserted += new FormViewInsertedEventHandler(EmployeeFormView_ItemInserted);
    employeesFormView.ItemInserting += new FormViewInsertEventHandler(EmployeeFormView_ItemInserting);

    // Create the dynamic templates using the custom template classes.
    employeesFormView.ItemTemplate = new EmployeeItemTemplate();
    employeesFormView.InsertItemTemplate = new EmployeeInsertItemTemplate();
    
    // Add the FormView object to the Controls collection
    // of the PlaceHolder control.
    FormViewPlaceHolder.Controls.Add(employeesFormView);

  }

  void EmployeeFormView_ItemInserting(Object sender, FormViewInsertEventArgs e)
  {
    
    // Because the FormView control is dynamically generated, 
    // the Values collection must be programmatically populated
    // with the values for the record to insert.

    // Use the sender argument to retrieve the FormView
    // control that raised the event.
    FormView employeeFormView = (FormView)sender;
    
    // Retrieve the data row from the FormView control.
    FormViewRow row = employeeFormView.Row;

    // Retrieve the TextBox controls that contain the values 
    // entered by the user for the new record. 
    TextBox firstNameTextBox = (TextBox)row.FindControl("FirstNameTextBox");
    TextBox lastNameTextBox = (TextBox)row.FindControl("LastNameTextBox");

    if (firstNameTextBox != null && lastNameTextBox != null)
    {
      // Add the new values to the Values collections.
      e.Values.Add("FirstName", firstNameTextBox.Text);
      e.Values.Add("LastName", lastNameTextBox.Text);
    }

  }

  void EmployeeFormView_ItemInserted(Object sender, FormViewInsertedEventArgs e)
  {
    // Use the Exception property to determine whether an exception
    // occurred during the insert operation.
    if (e.Exception == null)
    {
      // Use the AffectedRows property to determine whether the
      // record was inserted. Sometimes an error might occur that 
      // does not raise an exception, but prevents the insert
      // operation from completing.
      if (e.AffectedRows == 1)
      {
        MessageLabel.Text = "Record inserted successfully.";
      }
      else
      {
        MessageLabel.Text = "An error occurred during the insert operation.";
        
        // Use the KeepInInsertMode property to keep the control in 
        // insert mode when an error occurs during the insert operation.
        e.KeepInInsertMode = true;
      }
    }
    else
    {
      // Insert the code to handle the exception.
      MessageLabel.Text = e.Exception.Message;
      
      // Use the ExceptionHandled property to indicate that the 
      // exception has already been handled.
      e.ExceptionHandled = true;
      e.KeepInInsertMode = true;
    }
  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>FormView Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>FormView Example</h3>
      
      <!-- Use a PlaceHolder control as the container for the -->
      <!-- dynamically generated FormView control.            -->       
      <asp:placeholder id="FormViewPlaceHolder"
        runat="server"/>
      
      <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] From [Employees]"
        insertcommand="Insert Into [Employees] ([LastName], [FirstName]) VALUES (@LastName, @FirstName)"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" 
        runat="server"/>
            
    </form>
  </body>
</html>

Im folgenden Beispiel wird veranschaulicht, wie sie dem ItemInserted Ereignis eines Steuerelements deklarativ einen FormViewFormViewInsertedEventHandler Delegaten hinzufügen.

ASP.NET (C#) 

<%@ 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 EmployeeFormView_ItemInserted(Object sender, FormViewInsertedEventArgs e)
  {
    // Use the Exception property to determine whether an exception
    // occurred during the insert operation.
    if (e.Exception == null)
    {
      // Use the AffectedRows property to determine whether the
      // record was inserted. Sometimes an error might occur that 
      // does not raise an exception, but prevents the insert
      // operation from completing.
      if (e.AffectedRows == 1)
      {
        MessageLabel.Text = "Record inserted successfully.";
      }
      else
      {
        MessageLabel.Text = "An error occurred during the insert operation.";
        
        // Use the KeepInInsertMode property to keep the control in insert 
        // mode when an error occurs during the insert operation.
        e.KeepInInsertMode = true;
      }
    }
    else
    {
      // Insert the code to handle the exception.
      MessageLabel.Text = e.Exception.Message;
      
      // Use the ExceptionHandled property to indicate that the 
      // exception jhas already been handled.
      e.ExceptionHandled = true;
      e.KeepInInsertMode = true;
    }
  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>FormViewInsertedEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>FormViewInsertedEventHandler Example</h3>
                       
      <asp:formview id="EmployeeFormView"
        datasourceid="EmployeeSource"
        allowpaging="true"
        datakeynames="EmployeeID"
        emptydatatext="No employees found."
        oniteminserted="EmployeeFormView_ItemInserted"  
        runat="server">

        <itemtemplate>
          <table>
            <tr>
              <td rowspan="5">
                <asp:image id="CompanyLogoImage"
                  imageurl="~/Images/Logo.jpg"
                  alternatetext="Company logo"
                  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>
              <td colspan="2">
                <asp:linkbutton id="NewButton"
                  text="New"
                  commandname="New"
                  runat="server"/> 
              </td>
            </tr>
          </table>       
        </itemtemplate>
        <insertitemtemplate>
          <table>
            <tr>
              <td rowspan="4">
                <asp:image id="CompanyLogoEditImage"
                  imageurl="~/Images/Logo.jpg"
                  alternatetext="Company logo"
                  runat="server"/>
              </td>
              <td colspan="2">
                    
              </td>
            </tr>
            <tr>
              <td>
                <b>Name:</b>
              </td>
              <td>
                <asp:textbox id="FirstNameInsertTextBox"
                  text='<%# Bind("FirstName") %>'
                  runat="server"/>
                <asp:textbox id="LastNameInsertTextBox"
                  text='<%# Bind("LastName") %>'
                  runat="server"/>
              </td>
            </tr>
            <tr>
              <td>
                <b>Title:</b>
              </td>
              <td>
                <asp:textbox id="TitleInsertTextBox"
                  text='<%# Bind("Title") %>'
                  runat="server"/> 
              </td>
            </tr>
            <tr>
              <td colspan="2">
                <asp:linkbutton id="InsertButton"
                  text="Insert"
                  commandname="Insert"
                  runat="server"/>
                <asp:linkbutton id="CancelButton"
                  text="Cancel"
                  commandname="Cancel"
                  runat="server"/> 
              </td>
            </tr>
          </table>       
        </insertitemtemplate> 
                  
      </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], [PhotoPath] From [Employees]"
        insertcommand="Insert Into [Employees] ([LastName], [FirstName], [Title]) VALUES (@LastName, @FirstName, @Title)"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" 
        runat="server"/>
            
    </form>
  </body>
</html>

Hinweise

Das FormView -Steuerelement löst das ItemInserted Ereignis aus, wenn auf eine Einfügen-Schaltfläche (eine Schaltfläche mit CommandName der Eigenschaft "Einfügen") innerhalb des Steuerelements geklickt wird, aber nachdem das Steuerelement den FormView Datensatz eingefügt hat. Dadurch können Sie eine Ereignisbehandlungsmethode bereitstellen, die eine benutzerdefinierte Routine ausführt, z. B. die Überprüfung der Ergebnisse eines Einfügevorgangs, wenn dieses Ereignis auftritt.

Beim Erstellen eines FormViewInsertedEventHandler-Delegaten bestimmen Sie die Methode für die Ereignisbehandlung. Um dem Ereignishandler das Ereignis zuzuordnen, fügen Sie dem Ereignis eine Instanz des Delegaten hinzu. Der Ereignishandler wird bei jedem Eintreten des Ereignisses aufgerufen, sofern der Delegat nicht entfernt wird. Weitere Informationen zu Ereignishandlerdelegierten finden Sie unter Behandeln und Auslösen von Ereignissen.

Erweiterungsmethoden

GetMethodInfo(Delegate)

Ruft ein Objekt ab, das die Methode darstellt, die vom angegebenen Delegaten dargestellt wird.

Gilt für:

Produkt Versionen
.NET Framework 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1

Weitere Informationen