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FormViewUpdatedEventHandler مفوَّض

Visual Studio 2010

تمثل الطريقة التي يعالج ItemUpdatedحدث من FormViewعنصر تحكم.

مساحة الاسم:  System.Web.UI.WebControls
التجميع:  System.Web (في System.Web.dll)

public delegate void FormViewUpdatedEventHandler(
	Object sender,
	FormViewUpdatedEventArgs e
)

المعلمات

sender
النوع: System.Object
مصدر الحدث.
e
النوع: System.Web.UI.WebControls.FormViewUpdatedEventArgs
FormViewUpdatedEventArgs يحتوي على بيانات حدث.

FormView عنصر تحكم يرفع ItemUpdatedحدث عندما يظهر زر التحديث (زر مع به CommandNameتعيين الخاصية إلى "تحديث") داخل عنصر تحكم النقر فوق، ولكن بعد FormViewعنصر تحكم تحديث السجل. This allows you إلى provide an حدث-handling أسلوب that performs a مخصص routine, such كـ يتم الآن التدقيق the نتائج of an تحديث تشغيل, whenever this حدث occurs.

عندما تقوم بإنشاء FormViewUpdatedEventHandlerتفويض، تتعرف على الطريقة التي سيقوم بمعالجة حدث. لربط حدث مع معالج الأحداث الخاص بك، قم بإضافة مثيل تفويض للحدث. يتم استدعاء معالج حدث عند حدوث حدث، إلا إذا قمت بإزالة المفوض. للحصول على مزيد من المعلومات حول حدث-المفوضون معالج، راجع أحداث و مفوضون.

يوضح المثال التالي كيفية برمجياً إضافة FormViewUpdatedEventHandlerتفويض ItemUpdatedحدث من FormViewعنصر تحكم.



<%@ 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 editButton = new Button();
      editButton.ID = "EditButton";
      editButton.CommandName = "Edit";
      editButton.Text = "Edit";

      // 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(editButton);

    }

    // 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 edit item
  // template for a FormView control.
  private sealed class EmployeeEditItemTemplate : ITemplate
  {

    void ITemplate.InstantiateIn(Control container)
    {
      // Create the child controls contained in the template.
      // The edit item template should contain the input 
      // controls for the user to edit 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 updateButton = new Button();
      updateButton.ID = "UpdateButton";
      updateButton.CommandName = "Update";
      updateButton.Text = "Update";

      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(updateButton);
      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 
    // FormView control.
    employeesFormView.ItemUpdated += new FormViewUpdatedEventHandler(EmployeeFormView_ItemUpdated);
    employeesFormView.ItemUpdating += new FormViewUpdateEventHandler(EmployeeFormView_ItemUpdating);

    // Create the dynamic templates using the custom template classes.
    employeesFormView.ItemTemplate = new EmployeeItemTemplate();
    employeesFormView.EditItemTemplate = new EmployeeEditItemTemplate();

    // Add the FormView object to the Controls collection
    // of the PlaceHolder control.
    FormViewPlaceHolder.Controls.Add(employeesFormView);

  }

  void EmployeeFormView_ItemUpdating(Object sender, FormViewUpdateEventArgs e)
  {

    // Because the FormView control is dynamically generated, 
    // the NewValues collection must be programmatically populated
    // with the values for the record to update.

    // 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 updated values 
    // entered by the user. 
    TextBox firstNameTextBox = (TextBox)row.FindControl("FirstNameTextBox");
    TextBox lastNameTextBox = (TextBox)row.FindControl("LastNameTextBox");

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

  }

  void EmployeeFormView_ItemUpdated(Object sender, FormViewUpdatedEventArgs e)
  {
    // Use the Exception property to determine whether an exception
    // occurred during the update operation.
    if (e.Exception == null)
    {
      // Use the AffectedRows property to determine whether the
      // record was updated. Sometimes an error might occur that 
      // does not raise an exception, but prevents the update
      // operation from completing.
      if (e.AffectedRows == 1)
      {
        MessageLabel.Text = "Record updated successfully.";
      }
      else
      {
        MessageLabel.Text = "An error occurred during the update operation.";

        // Use the KeepInUpdateMode property to keep the control in edit mode
        // when an error occurs during the update operation.
        e.KeepInEditMode = 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.KeepInEditMode = 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]"
        updatecommand="Update [Employees] Set [LastName]=@LastName, [FirstName]=@FirstName Where [EmployeeID]=@EmployeeID"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" 
        runat="server"/>

    </form>
  </body>
</html>



يوضح المثال التالي كيفية إضافة بشكل إلزامي FormViewUpdatedEventHandlerتفويض ItemUpdatedحدث من FormViewعنصر تحكم.



<%@ 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_ItemUpdated(Object sender, FormViewUpdatedEventArgs 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["EmployeeID"].ToString();

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

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

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

  void DisplayValues(OrderedDictionary newValues, OrderedDictionary oldValues)
  {

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

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

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

  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>FormViewUpdatedEventArgs Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <h3>FormViewUpdatedEventArgs Example</h3>

      <asp:formview id="EmployeeFormView"
        datasourceid="EmployeeSource"
        allowpaging="true"
        datakeynames="EmployeeID"
        emptydatatext="No employees found."
        onitemupdated="EmployeeFormView_ItemUpdated"   
        runat="server">

        <itemtemplate>
          <table>
            <tr>
              <td rowspan="6">
                <asp:image id="EmployeeImage"
                  imageurl='<%# Eval("PhotoPath") %>'
                  alternatetext='<%# Eval("LastName") %>' 
                  runat="server"/>
              </td>
              <td colspan="2">
                  &nbsp; 
              </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>
                <b>Hire Date:</b>                 
              </td>
              <td>
                <%# Eval("HireDate","{0:d}") %>
              </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">
                  &nbsp; 
              </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>



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مدعوم في: 4, 3.5, 3.0, 2.0
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