DataControlFieldCollection.Add メソッドとは何？わかりやすく解説 Weblio辞書

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DataControlFieldCollection.Add メソッド

メモ : このメソッドは、.NET Framework version 2.0 で新しく追加されたものです。

指定した DataControlField オブジェクトをコレクションの末尾に追加します。

名前空間: System.Web.UI.WebControls
アセンブリ: System.Web (system.web.dll 内)
構文

Visual Basic (宣言)

Public Sub Add ( _
    field As DataControlField _
)

Visual Basic (使用法)

Dim instance As DataControlFieldCollection
Dim field As DataControlField

instance.Add(field)

public void Add (
    DataControlField field
)

C++

public:
void Add (
    DataControlField^ field
)

public void Add (
    DataControlField field
)

JScript

public function Add (
    field : DataControlField
)

パラメータ

field: コレクションの末尾に追加する DataControlField。

解説

Add メソッドを使用して、DataControlField オブジェクトをコレクションの末尾に追加します。このメソッドの実装は、field パラメータで指定された DataControlField オブジェクトを取得し、その項目をコレクションに追加します。

使用例

Add メソッドを使用して、CheckBoxField オブジェクトを GridView コントロールに動的に追加する方法を次のコード例に示します。

Visual Basic

<%@ Page language="VB" %>

<script runat="server">

  Sub Page_Load(sender as Object,
 e As EventArgs)
  
    ' The columns need to be created only the first time
    ' the page is loaded.
    If Not IsPostBack Then

      ' Dynamically create columns to display the desired
      ' fields from the data source. Columns that are 
      ' dynamically added to the GridView control are not persisted
 
      ' across posts and must be recreated each time the page is 
      ' loaded.
  
      ' Create a BoundField object to display an author's last name.
      Dim lastNameBoundField As BoundField
 = New BoundField
      lastNameBoundField.DataField = "au_lname"
      lastNameBoundField.HeaderText = "Last Name"
    
      ' Create a CheckBoxField object to indicate whether the author
      ' is on contract.
      Dim contractCheckBoxField As CheckBoxField
 = New CheckBoxField
      contractCheckBoxField.DataField = "contract"
      contractCheckBoxField.HeaderText = "Contract"
    
      ' Add the columns to the Columns collection of the
      ' GridView control.
      AuthorsGridView.Columns.Add(lastNameBoundField)
      AuthorsGridView.Columns.Add(contractCheckBoxField)

    End If
  
  End Sub

</script>

<html>
  <body>
    <form runat="server">
        
      <h3>CheckBoxField 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_lname], [au_fname], [address],
 [city], [state], [zip], [contract] FROM [authors]"
        connectionstring="server=localhost;database=pubs;integrated
 security=SSPI"
        runat="server">
      </asp:sqldatasource>
            
    </form>
  </body>
</html>

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

<script runat="server">

  void Page_Load(Object sender, EventArgs e)
  {

    // The columns need to be created only the first time
    // the page is loaded.
    if(!IsPostBack)
    {
  
      // Dynamically create columns to display the desired
      // fields from the data source. Columns that are 
      // dynamically added to the GridView control are not persisted
 
      // across posts and must be recreated each time the page is 
      // loaded.
  
      // Create a BoundField object to display an author's last name.
      BoundField lastNameBoundField = new BoundField();
      lastNameBoundField.DataField = "au_lname";
      lastNameBoundField.HeaderText = "Last Name";
    
      // Create a CheckBoxField object to indicate whether the author
      // is on contract.
      CheckBoxField contractCheckBoxField = new CheckBoxField();
      contractCheckBoxField.DataField = "contract";
      contractCheckBoxField.HeaderText = "Contract";
    
      // Add the columns to the Columns collection of the
      // GridView control.
      AuthorsGridView.Columns.Add(lastNameBoundField);
      AuthorsGridView.Columns.Add(contractCheckBoxField);

    }
  
  }

</script>

<html>
  <body>
    <form runat="server">
        
      <h3>CheckBoxField 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_lname], [au_fname], [address], [city], [state],
 [zip], [contract] FROM [authors]"
        connectionstring="server=localhost;database=pubs;integrated security=SSPI"
        runat="server">
      </asp:sqldatasource>
            
    </form>
  </body>
</html>