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ImageField.DataAlternateTextField 屬性

  • 參考

定義

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

取得或設定資料來源中的欄位名稱，這個欄位的值將繫結至 AlternateText 物件中每個影像的 ImageField 屬性。

public:
 virtual property System::String ^ DataAlternateTextField { System::String ^ get(); void set(System::String ^ value); };
[System.ComponentModel.TypeConverter("System.Web.UI.Design.DataSourceViewSchemaConverter, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")]
public virtual string DataAlternateTextField { get; set; }
[System.ComponentModel.TypeConverter("System.Web.UI.Design.DataSourceViewSchemaConverter, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")]
public virtual string DataAlternateTextField { get; set; }
[<System.ComponentModel.TypeConverter("System.Web.UI.Design.DataSourceViewSchemaConverter, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")>]
member this.DataAlternateTextField : string with get, set
[<System.ComponentModel.TypeConverter("System.Web.UI.Design.DataSourceViewSchemaConverter, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")>]
member this.DataAlternateTextField : string with get, set
Public Overridable Property DataAlternateTextField As String

屬性值

String

欄位名稱，這個欄位將繫結 AlternateText 物件中每個影像的 ImageField 屬性。

屬性
TypeConverterAttribute

範例

下列範例程式碼示範如何使用 DataAlternateTextField 屬性，從資料來源指定功能變數名稱，其中包含要系結至 AlternateText 物件中 ImageField 每個影像之屬性的值。


<%@ Page language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ImageField Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>ImageField Example</h3>
                       
      <asp:gridview id="EmployeesGrid"
        autogeneratecolumns="false"
        datasourceid="EmployeeSource"  
        runat="server">
      
        <columns>

          <asp:imagefield dataimageurlfield="PhotoPath"
            dataalternatetextfield="LastName"
            dataalternatetextformatstring="Photo: {0}" 
            nulldisplaytext="No image on file."
            headertext="Photo"  
            readonly="true"/>
          <asp:boundfield datafield="FirstName"
            headertext="First Name"/>
          <asp:boundfield datafield="LastName"
            headertext="Last Name"/>
        
        </columns>
        
      </asp:gridview>
          
      <!-- 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], [PhotoPath] From [Employees]"
        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">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ImageField Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>ImageField Example</h3>
                       
      <asp:gridview id="EmployeesGrid"
        autogeneratecolumns="false"
        datasourceid="EmployeeSource"  
        runat="server">
      
        <columns>

          <asp:imagefield dataimageurlfield="PhotoPath"
            dataalternatetextfield="LastName"
            dataalternatetextformatstring="Photo: {0}" 
            nulldisplaytext="No image on file."
            headertext="Photo"  
            readonly="true"/>
          <asp:boundfield datafield="FirstName"
            headertext="First Name"/>
          <asp:boundfield datafield="LastName"
            headertext="Last Name"/>
        
        </columns>
        
      </asp:gridview>
          
      <!-- 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], [PhotoPath] From [Employees]"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" 
        runat="server"/>
            
    </form>
  </body>
</html>

備註

DataAlternateTextField使用 屬性可指定資料來源中包含要系結至 AlternateText 物件中 ImageField 每個影像之屬性之值的欄位名稱。 可讓您針對每個顯示的影像有不同的替代文字。 當無法載入或無法使用影像時，會顯示替代文字。 支援工具提示功能的瀏覽器也會將此文字顯示為工具提示。

注意

您可以藉由設定 AlternateText 屬性而非此屬性，指定套用至所有影像的替代文字。 如果 同時 AlternateText 設定 和 DataAlternateTextField 屬性，則 DataAlternateTextField 欄位會優先使用。

適用於

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