TreeNodeSelectAction 列挙体とは何？わかりやすく解説 Weblio辞書

.NET Framework クラスライブラリリファレンス

索引トップ用語の索引ランキング

TreeNodeSelectAction 列挙体

メモ : この列挙体は、.NET Framework version 2.0 で新しく追加されたものです。

TreeView コントロール内のノードが選択されたときに発生させる 1 つ以上のイベントを表します。

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 Enumeration TreeNodeSelectAction

Visual Basic (使用法)

Dim instance As TreeNodeSelectAction

public enum TreeNodeSelectAction

C++

public enum class TreeNodeSelectAction

public enum TreeNodeSelectAction

JScript

public enum TreeNodeSelectAction

メンバ

	メンバ名	説明
	Expand	ノードの選択時に TreeNodeExpanded イベントを発生させます。
	None	ノードの選択時にイベントは発生しません。
	Select	ノードの選択時に SelectedNodeChanged イベントを発生させます。
	SelectExpand	ノードの選択時に SelectedNodeChanged イベントと TreeNodeExpanded イベントの両方を発生させます。

解説

TreeNode コントロールの NavigateUrl プロパティに空の文字列 ("") 以外の値を設定した場合、ノードがクリックされると、指定した URL に移動します。NavigateUrl プロパティに空の文字列を設定した場合、ノードがクリックされると、ポストバックが発生します。SelectAction プロパティは、ポストバックで発生させるイベントを決定します。既定では、Select イベントが発生します。NavigateUrl プロパティが設定されている場合、イベントは発生しません。

メモ
SelectAction プロパティが None 値に設定されているノードでは、HoverNodeStyle プロパティは表示されません。

使用例

次のコード例では、TreeNodeSelectAction 列挙値を使用して、TreeView コントロール内のノードがクリックされたときに発生させるイベントを表す方法を示します。

Visual Basic

<%@ Page Language="VB" %>
<%@ Import Namespace="System.Data"
 %>
<%@ Import Namespace="System.Data.SqlClient"
 %>

<script runat="server">

  Sub PopulateNode(ByVal sender As
 Object, ByVal e As TreeNodeEventArgs)

    ' Call the appropriate method to populate a node at a particular
 level.
    Select Case e.Node.Depth

      Case 0
        ' Populate the first-level nodes.
        PopulateCategories(e.Node)

      Case 1
        ' Populate the second-level nodes.
        PopulateProducts(e.Node)

      Case Else
        ' Do nothing.

    End Select

  End Sub

  Sub PopulateCategories(ByVal node As
 TreeNode)

    ' Query for the product categories. These are the values
    ' for the second-level nodes.
    Dim ResultSet As DataSet = RunQuery("Select
 CategoryID, CategoryName From Categories")

    ' Create the second-level nodes.
    If ResultSet.Tables.Count > 0 Then

      ' Iterate through and create a new node for each row in the query
 results.
      ' Notice that the query results are stored in the table of the
 DataSet.
      Dim row As DataRow

      For Each row In ResultSet.Tables(0).Rows

        ' Create the new node. Notice that the CategoryId is stored
 in the Value property 
        ' of the node. This will make querying for items in a specific
 category easier when
        ' the third-level nodes are created. 
        Dim newNode As TreeNode = New
 TreeNode()
        Newnode.Text = row("CategoryName").ToString()
 
        Newnode.Value = row("CategoryID").ToString()

        ' Set the PopulateOnDemand property to true so that the child
 nodes can be 
        ' dynamically populated.
        newNode.PopulateOnDemand = True

        ' Set additional properties for the node.
        newNode.SelectAction = TreeNodeSelectAction.Expand

        ' Add the new node to the ChildNodes collection of the parent
 node.
        node.ChildNodes.Add(newNode)

      Next

    End If

  End Sub

  Sub PopulateProducts(ByVal node As
 TreeNode)

    ' Query for the products of the current category. These are the
 values
    ' for the third-level nodes.
    Dim ResultSet As DataSet = RunQuery("Select
 ProductName From Products Where CategoryID=" & node.Value)

    ' Create the third-level nodes.
    If ResultSet.Tables.Count > 0 Then

      ' Iterate through and create a new node for each row in the query
 results.
      ' Notice that the query results are stored in the table of the
 DataSet.
      Dim row As DataRow

      For Each row In ResultSet.Tables(0).Rows

        ' Create the new node.
        Dim NewNode As TreeNode = New
 TreeNode(row("ProductName").ToString())

        ' Set the PopulateOnDemand property to false, because these
 are leaf nodes and
        ' do not need to be populated.
        NewNode.PopulateOnDemand = False

        ' Set additional properties for the node.
        NewNode.SelectAction = TreeNodeSelectAction.None

        ' Add the new node to the ChildNodes collection of the parent
 node.
        node.ChildNodes.Add(NewNode)

      Next

    End If

  End Sub

  Function RunQuery(ByVal QueryString As
 String) As DataSet

    ' Declare the connection string. This example uses Microsoft SQL
 Server 
    ' and connects to the Northwind sample database.
    Dim ConnectionString As String
 = "server=localhost;database=NorthWind;Integrated Security=SSPI"

    Dim DBConnection As SqlConnection = New
 SqlConnection(ConnectionString)
    Dim DBAdapter As SqlDataAdapter
    Dim ResultsDataSet As DataSet = New
 DataSet

    Try

      ' Run the query and create a DataSet.
      DBAdapter = New SqlDataAdapter(QueryString, DBConnection)
      DBAdapter.Fill(ResultsDataSet)

      ' Close the database connection.
      DBConnection.Close()

    Catch ex As Exception

      ' Close the database connection if it is still open.
      If DBConnection.State = ConnectionState.Open Then

        DBConnection.Close()

      End If

      Message.Text = "Unable to connect to the database."

    End Try

    Return ResultsDataSet

  End Function

</script>

<html>
  <body>
    <form runat="server">
    
      <h3>TreeView PopulateNodesFromClient Example</h3>
    
      <asp:TreeView id="LinksTreeView"
        Font-Name= "Arial"
        ForeColor="Blue"
        EnableClientScript="true"
        PopulateNodesFromClient="true"  
        OnTreeNodePopulate="PopulateNode"
        runat="server">
         
        <Nodes>
        
          <asp:TreeNode Text="Inventory" 
            SelectAction="Expand"  
            PopulateOnDemand="true"/>
        
        </Nodes>
        
      </asp:TreeView>
      
      <br><br>
      
      <asp:Label id="Message" runat="server"/>

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

<%@ Page Language="C#" %>
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.SqlClient" %>

<script runat="server">

  void PopulateNode(Object sender, TreeNodeEventArgs e)
  {

    // Call the appropriate method to populate a node at a particular
 level.
    switch(e.Node.Depth)
    {
      case 0:
        // Populate the first-level nodes.
        PopulateCategories(e.Node);
        break;
      case 1:
        // Populate the second-level nodes.
        PopulateProducts(e.Node);
        break;
      default:
        // Do nothing.
        break;
    }
    
  }

  void PopulateCategories(TreeNode node)
  {
    
    // Query for the product categories. These are the values
    // for the second-level nodes.
    DataSet ResultSet = RunQuery("Select CategoryID, CategoryName From Categories");

    // Create the second-level nodes.
    if(ResultSet.Tables.Count > 0)
    {
    
      // Iterate through and create a new node for each row in the query
 results.
      // Notice that the query results are stored in the table of the
 DataSet.
      foreach (DataRow row in ResultSet.Tables[0].Rows)
      {
        
        // Create the new node. Notice that the CategoryId is stored
 in the Value property 
        // of the node. This will make querying for items in a specific
 category easier when
        // the third-level nodes are created. 
        TreeNode newNode = new TreeNode();
        newNode.Text = row["CategoryName"].ToString(); 
        newNode.Value = row["CategoryID"].ToString();        

        // Set the PopulateOnDemand property to true so that the child
 nodes can be 
        // dynamically populated.
        newNode.PopulateOnDemand = true;
        
        // Set additional properties for the node.
        newNode.SelectAction = TreeNodeSelectAction.Expand;
        
        // Add the new node to the ChildNodes collection of the parent
 node.
        node.ChildNodes.Add(newNode);
        
      }
      
    }
    
  }

  void PopulateProducts(TreeNode node)
  {

    // Query for the products of the current category. These are the
 values
    // for the third-level nodes.
    DataSet ResultSet = RunQuery("Select ProductName From Products Where CategoryID="
 + node.Value);

    // Create the third-level nodes.
    if(ResultSet.Tables.Count > 0)
    {
    
      // Iterate through and create a new node for each row in the query
 results.
      // Notice that the query results are stored in the table of the
 DataSet.
      foreach (DataRow row in ResultSet.Tables[0].Rows)
      {
      
        // Create the new node.
        TreeNode NewNode = new TreeNode(row["ProductName"].ToString());
        
        // Set the PopulateOnDemand property to false, because these
 are leaf nodes and
        // do not need to be populated.
        NewNode.PopulateOnDemand = false;
        
        // Set additional properties for the node.
        NewNode.SelectAction = TreeNodeSelectAction.None;
        
        // Add the new node to the ChildNodes collection of the parent
 node.
        node.ChildNodes.Add(NewNode);
        
      }
      
    }

  }

  DataSet RunQuery(String QueryString)
  {

    // Declare the connection string. This example uses Microsoft SQL
 Server 
    // and connects to the Northwind sample database.
    String ConnectionString = "server=localhost;database=NorthWind;Integrated
 Security=SSPI"; 

    SqlConnection DBConnection = new SqlConnection(ConnectionString);
    SqlDataAdapter DBAdapter;
    DataSet ResultsDataSet = new DataSet();

    try
    {

      // Run the query and create a DataSet.
      DBAdapter = new SqlDataAdapter(QueryString, DBConnection);
      DBAdapter.Fill(ResultsDataSet);

      // Close the database connection.
      DBConnection.Close();

    }
    catch(Exception ex)
    {

      // Close the database connection if it is still open.
      if(DBConnection.State == ConnectionState.Open)
      {
        DBConnection.Close();
      }
      
      Message.Text = "Unable to connect to the database.";

    }

    return ResultsDataSet;

  }

</script>

<html>
  <body>
    <form runat="server">
    
      <h3>TreeView PopulateNodesFromClient Example</h3>
    
      <asp:TreeView id="LinksTreeView"
        Font-Name= "Arial"
        ForeColor="Blue"
        EnableClientScript="true"
        PopulateNodesFromClient="true"  
        OnTreeNodePopulate="PopulateNode"
        runat="server">
         
        <Nodes>
        
          <asp:TreeNode Text="Inventory" 
            SelectAction="Expand"  
            PopulateOnDemand="true"/>
        
        </Nodes>
        
      </asp:TreeView>
      
      <br><br>
      
      <asp:Label id="Message" runat="server"/>

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

プラットフォーム

Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0

参照

関連項目
System.Web.UI.WebControls 名前空間
TreeView
SelectedNode
TreeNode クラス
TreeNode.SelectAction プロパティ
SelectedNodeChanged
TreeNodeExpanded

>> 「TreeNodeSelectAction 列挙体」を含む用語の索引
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TreeNodeSelectAction 列挙体とは？ わかりやすく解説

TreeNodeSelectAction 列挙体

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TreeNodeSelectAction 列挙体とは？わかりやすく解説