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TemplateField 建構函式

  • 參考

定義

命名空間:
System.Web.UI.WebControls
組件:
System.Web.dll

初始化 TemplateField 類別的新執行個體。

C# 
public TemplateField();

範例

下列程式碼範例示範如何使用 建構函式，以動態方式將欄位資料行 GridView 加入 TemplateField 控制項。

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">
  
  // Create a template class to represent a dynamic template column.
  public class GridViewTemplate : ITemplate
  {
    private DataControlRowType templateType;
    private string columnName;
   
    public GridViewTemplate(DataControlRowType type, string colname)
    {
      templateType = type;
      columnName = colname;
    }

    public void InstantiateIn(System.Web.UI.Control container)
    {
      // Create the content for the different row types.
      switch(templateType)
      {
        case DataControlRowType.Header:
          // Create the controls to put in the header
          // section and set their properties.
          Literal lc = new Literal();
          lc.Text = "<b>" + columnName + "</b>";
          
          // Add the controls to the Controls collection
          // of the container.
          container.Controls.Add(lc);
          break;
        case DataControlRowType.DataRow:
          // Create the controls to put in a data row
          // section and set their properties.
          Label firstName = new Label();
          Label lastName = new Label();
          
          Literal spacer = new Literal();
          spacer.Text = " ";
          
          // To support data binding, register the event-handling methods
          // to perform the data binding. Each control needs its own event
          // handler.
          firstName.DataBinding += new EventHandler(this.FirstName_DataBinding);
          lastName.DataBinding += new EventHandler(this.LastName_DataBinding);
          
          // Add the controls to the Controls collection
          // of the container.
          container.Controls.Add(firstName);
          container.Controls.Add (spacer);
          container.Controls.Add(lastName);
          break;
          
        // Insert cases to create the content for the other 
        // row types, if desired.
          
        default:
          // Insert code to handle unexpected values.
          break; 
      }
    }
    
    private void FirstName_DataBinding(Object sender, EventArgs e)
    {
      // Get the Label control to bind the value. The Label control
      // is contained in the object that raised the DataBinding 
      // event (the sender parameter).
      Label l = (Label)sender;
      
      // Get the GridViewRow object that contains the Label control. 
      GridViewRow row = (GridViewRow)l.NamingContainer;
      
      // Get the field value from the GridViewRow object and 
      // assign it to the Text property of the Label control.
      l.Text = DataBinder.Eval(row.DataItem, "au_fname").ToString();
    }
    
    private void LastName_DataBinding(Object sender, EventArgs e)
    { 
      // Get the Label control to bind the value. The Label control
      // is contained in the object that raised the DataBinding 
      // event (the sender parameter).
      Label l = (Label)sender;
      
      // Get the GridViewRow object that contains the Label control.
      GridViewRow row = (GridViewRow)l.NamingContainer;
      
      // Get the field value from the GridViewRow object and 
      // assign it to the Text property of the Label control.
      l.Text = DataBinder.Eval(row.DataItem, "au_lname").ToString();
    }
  }

  void Page_Load(Object sender, EventArgs e)
  {
    
    // The field columns need to be created only when the page is
    // first loaded. 
    if (!IsPostBack)
    {
      // Dynamically create field columns to display the desired
      // fields from the data source. Create a TemplateField object 
      // to display an author's first and last name.
      TemplateField customField = new TemplateField();

      // Create the dynamic templates and assign them to 
      // the appropriate template property.
      customField.ItemTemplate = new GridViewTemplate(DataControlRowType.DataRow, "Author Name");
      customField.HeaderTemplate = new GridViewTemplate(DataControlRowType.Header, "Author Name");

      // Add the field column to the Columns collection of the
      // GridView control.
      AuthorsGridView.Columns.Add(customField);
    }
  
  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>TemplateField Constructor Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>TemplateField Constructor Example</h3>

      <asp:gridview id="AuthorsGridView" 
        datasourceid="AuthorsSqlDataSource" 
        autogeneratecolumns="False"
        runat="server">                
      </asp:gridview>
            
      <!-- This example uses Microsoft SQL Server and connects -->
      <!-- to the Pubs sample database.                        -->
      <asp:sqldatasource id="AuthorsSqlDataSource"  
        selectcommand="SELECT [au_fname], [au_lname] FROM [authors]"
        connectionstring="server=localhost;database=pubs;integrated security=SSPI"
        runat="server">
      </asp:sqldatasource>
            
    </form>
  </body>
</html>

備註

使用此建構函式來初始化 類別的新實例 TemplateField 。 這個建構函式通常會在將欄位新增至動態建立的資料繫結控制項時使用。

若要動態將物件新增 TemplateField 至資料繫結控制項，請建立新的 TemplateField 物件、定義適當的範本，然後將它新增至資料繫結控制項的欄位集合。 例如，如果您使用 GridView 控制項，請將 TemplateField 物件新增至 Columns 集合。

注意

雖然您可以動態將欄位新增至資料繫結控制項，但強烈建議以靜態方式宣告欄位，然後視需要顯示或隱藏欄位。 以靜態方式宣告所有欄位會減少父資料繫結控制項的檢視狀態大小。

適用於

產品 版本
.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

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