ItemCheckEventArgs.CurrentValue プロパティ

.NET Framework クラス ライブラリ リファレンス

ItemCheckEventArgs.CurrentValue プロパティ

項目のチェック ボックスの現在の状態を示す値を取得します。

名前空間: System.Windows.Forms
アセンブリ: System.Windows.Forms (system.windows.forms.dll 内)
構文

Visual Basic (宣言)

Public ReadOnly Property
 CurrentValue As CheckState

Visual Basic (使用法)

Dim instance As ItemCheckEventArgs
Dim value As CheckState

value = instance.CurrentValue

C#

public CheckState CurrentValue { get; }

C++

public:
property CheckState CurrentValue {
    CheckState get ();
}

J#

/** @property */
public CheckState get_CurrentValue ()

JScript

public function get CurrentValue
 () : CheckState

プロパティ値
CheckState 値の 1 つ。

解説

このプロパティにより、チェック状態の変更が適用される前に CheckedListBox の指定された項目のチェック状態を判断できます。

使用例

チェックされている ListView コントロールが ListView.ItemChecked イベントを処理するようすを次のコード例に示します。このメソッドは ItemCheckEventArgs オブジェクトの CurrentValue プロパティと Index プロパティを使用して、選択されているメニュー項目の価格を取得して計算します。この例を実行するには、ListView1 という名前の ListView と Textbox1 という名前の TextBox が配置されているフォームに、次のコードを貼り付けます。そして、フォームのコンストラクタまたはLoad メソッドから InititalizeListView メソッドを呼び出します。必ずすべてのイベントをイベント処理メソッドに関連付けるようにしてください。

Visual Basic

    Private Sub InitializeListView()
        Me.ListView1 = New System.Windows.Forms.ListView

        ' Set properties such as BackColor, Location and Size
        Me.ListView1.BackColor = System.Drawing.SystemColors.Control
        Me.ListView1.Dock = System.Windows.Forms.DockStyle.Top
        Me.ListView1.Location = New System.Drawing.Point(0,
 0)
        Me.ListView1.Size = New System.Drawing.Size(292,
 130)
        Me.ListView1.View = System.Windows.Forms.View.Details
        Me.ListView1.HideSelection = False

        ' Allow user to select multiple items.
        Me.ListView1.MultiSelect = True

        ' Show check boxes in the ListView.
        Me.ListView1.CheckBoxes = True

        'Set the column headers and populate the columns.
        ListView1.HeaderStyle = ColumnHeaderStyle.Nonclickable
        Dim columnHeader1 As New
 ColumnHeader
        With columnHeader1
            .Text = "Breakfast Choices"
            .TextAlign = HorizontalAlignment.Left
            .Width = 146
        End With
        Dim columnHeader2 As New
 ColumnHeader
        With columnHeader2
            .Text = "Price Each"
            .TextAlign = HorizontalAlignment.Center
            .Width = 142
        End With
        Me.ListView1.Columns.Add(columnHeader1)
        Me.ListView1.Columns.Add(columnHeader2)
        Dim foodList() As String
 = New String() {"Juice",
 "Coffee", _
            "Cereal & Milk", "Fruit
 Plate", "Toast & Jelly", _
            "Bagel & Cream Cheese"}

        Dim foodPrice() As String
 = New String() {"1.09",
 "1.09", "2.19", _
            "2.79", "2.09",
 "2.69"}
        Dim count As Integer

        ' Members are added one at a time, so call BeginUpdate to ensure
 
        ' the list is painted only once, rather than as each list item
 is added.
        ListView1.BeginUpdate()

        For count = 0 To foodList.Length -
 1
            Dim listItem As New
 ListViewItem(foodList(count))
            listItem.SubItems.Add(foodPrice(count))
            ListView1.Items.Add(listItem)
        Next

        'Call EndUpdate when you finish adding items to the ListView.
        ListView1.EndUpdate()
        Me.Controls.Add(Me.ListView1)
    End Sub
<br /><span space="preserve">...</span><br
 />    Dim price As Double
 = 0.0

    ' Handles the ItemChecked event. The method uses the CurrentValue
 property 
    ' of the ItemCheckEventArgs to retrieve and tally the price of the
 menu 
    ' items selected.  
    Private Sub ListView1_ItemCheck1(ByVal
 sender As Object, _
        ByVal e As System.Windows.Forms.ItemCheckEventArgs)
 _
        Handles ListView1.ItemCheck

        If (e.CurrentValue = CheckState.Unchecked) Then
            price += Double.Parse( _
            Me.ListView1.Items(e.Index).SubItems(1).Text)
        ElseIf (e.CurrentValue = CheckState.Checked) Then
            price -= Double.Parse( _
                Me.ListView1.Items(e.Index).SubItems(1).Text)
        End If

        ' Output the price to TextBox1.
        TextBox1.Text = CType(price, String)

    End Sub

C#

    private void InitializeListView()
    {
        this.ListView1 = new System.Windows.Forms.ListView();

        // Set properties such as BackColor and DockStyle and Location.
        this.ListView1.BackColor = System.Drawing.SystemColors.Control;
        this.ListView1.Dock = System.Windows.Forms.DockStyle.Top;
        this.ListView1.Location = new System.Drawing.Point(0,
 0);
        this.ListView1.Size = new System.Drawing.Size(292,
 130);
        this.ListView1.View = System.Windows.Forms.View.Details;
        this.ListView1.HideSelection = false;

        // Allow the user to select multiple items.
        this.ListView1.MultiSelect = true;

        // Show CheckBoxes in the ListView.
        this.ListView1.CheckBoxes = true;
        
        //Set the column headers and populate the columns.
        ListView1.HeaderStyle = ColumnHeaderStyle.Nonclickable;
        
        ColumnHeader columnHeader1 = new ColumnHeader();
        columnHeader1.Text = "Breakfast Choices";
        columnHeader1.TextAlign = HorizontalAlignment.Left;
        columnHeader1.Width = 146;

        ColumnHeader columnHeader2 = new ColumnHeader();
        columnHeader2.Text = "Price Each";
        columnHeader2.TextAlign = HorizontalAlignment.Center;
        columnHeader2.Width = 142;

           this.ListView1.Columns.Add(columnHeader1);
        this.ListView1.Columns.Add(columnHeader2);

        string[] foodList = new string[]{"Juice",
 "Coffee", 
            "Cereal & Milk", "Fruit Plate", "Toast &
 Jelly", 
            "Bagel & Cream Cheese"};

        string[] foodPrice = new string[]{"1.09",
 "1.09", "2.19", 
            "2.79", "2.09", "2.69"};
        
        int count;

        // Members are added one at a time, so call BeginUpdate to ensure
 
        // the list is painted only once, rather than as each list item
 is added.
        ListView1.BeginUpdate();

        for(count = 0; count < foodList.Length; count++)
        {
            ListViewItem listItem = new ListViewItem(foodList[count]);
            listItem.SubItems.Add(foodPrice[count]);
            ListView1.Items.Add(listItem);
        }

        //Call EndUpdate when you finish adding items to the ListView.
        ListView1.EndUpdate();
        this.Controls.Add(this.ListView1);
    }
<br /><span space="preserve">...</span><br /> 
   double price = 0.0;

    // Handles the ItemCheck event. The method uses the CurrentValue
    // property of the ItemCheckEventArgs to retrieve and tally the
  
    // price of the menu items selected.  
    private void ListView1_ItemCheck1(object
 sender, 
        System.Windows.Forms.ItemCheckEventArgs e)
    {
        if (e.CurrentValue==CheckState.Unchecked)
        {
            price += Double.Parse(
                this.ListView1.Items[e.Index].SubItems[1].Text);
        }
        else if((e.CurrentValue==CheckState.Checked))
        {
            price -= Double.Parse(
                this.ListView1.Items[e.Index].SubItems[1].Text);
        }

        // Output the price to TextBox1.
        TextBox1.Text = price.ToString();
    }

C++

   void InitializeListView()
   {
      this->ListView1 = gcnew System::Windows::Forms::ListView;
      
      // Set properties such as BackColor and DockStyle and Location.
      this->ListView1->BackColor = System::Drawing::SystemColors::Control;
      this->ListView1->Dock = System::Windows::Forms::DockStyle::Top;
      this->ListView1->Location = System::Drawing::Point(
 0, 0 );
      this->ListView1->Size = System::Drawing::Size( 292,
 130 );
      this->ListView1->View = System::Windows::Forms::View::Details;
      this->ListView1->HideSelection = false;
      
      // Allow the user to select multiple items.
      this->ListView1->MultiSelect = true;
      
      // Show CheckBoxes in the ListView.
      this->ListView1->CheckBoxes = true;
      
      //Set the column headers and populate the columns.
      ListView1->HeaderStyle = ColumnHeaderStyle::Nonclickable;
      ColumnHeader^ columnHeader1 = gcnew ColumnHeader;
      columnHeader1->Text = "Breakfast Choices";
      columnHeader1->TextAlign = HorizontalAlignment::Left;
      columnHeader1->Width = 146;
      ColumnHeader^ columnHeader2 = gcnew ColumnHeader;
      columnHeader2->Text = "Price Each";
      columnHeader2->TextAlign = HorizontalAlignment::Center;
      columnHeader2->Width = 142;
      this->ListView1->Columns->Add( columnHeader1 );
      this->ListView1->Columns->Add( columnHeader2 );
      array<String^>^foodList = {"Juice","Coffee","Cereal
 & Milk","Fruit Plate","Toast & Jelly","Bagel
 & Cream Cheese"};
      array<String^>^foodPrice = {"1.09","1.09","2.19"
,"2.79","2.09","2.69"};
      int count;
      
      // Members are added one at a time, so call BeginUpdate to ensure
 
      // the list is painted only once, rather than as each list item
 is added.
      ListView1->BeginUpdate();
      for ( count = 0; count < foodList->Length; count++
 )
      {
         ListViewItem^ listItem = gcnew ListViewItem( foodList[ count ] );
         listItem->SubItems->Add( foodPrice[ count ] );
         ListView1->Items->Add( listItem );
      }
      
      //Call EndUpdate when you finish adding items to the ListView.
      ListView1->EndUpdate();
      this->Controls->Add( this->ListView1
 );
   }
<br /><span space="preserve">...</span><br /> 
  double price;

   // Handles the ItemCheck event. The method uses the CurrentValue
   // property of the ItemCheckEventArgs to retrieve and tally the 
 
   // price of the menu items selected.  
   void ListView1_ItemCheck1( Object^ /*sender*/, System::Windows::Forms::ItemCheckEventArgs^
 e )
   {
      if ( e->CurrentValue == CheckState::Unchecked )
      {
         price += Double::Parse( this->ListView1->Items[
 e->Index ]->SubItems[ 1 ]->Text );
      }
      else
      if ( (e->CurrentValue == CheckState::Checked) )
      {
         price -= Double::Parse( this->ListView1->Items[
 e->Index ]->SubItems[ 1 ]->Text );
      }


      
      // Output the price to TextBox1.
      TextBox1->Text = price.ToString();
   }

J#

    private void InitializeListView()
    {
        this.listView1 = new System.Windows.Forms.ListView();
        // Set properties such as BackColor and DockStyle and Location.
        this.listView1.set_BackColor(System.Drawing.SystemColors.get_Control());
        this.listView1.set_Dock(System.Windows.Forms.DockStyle.Top);
        this.listView1.set_Location(new System.Drawing.Point(0,
 0));
        this.listView1.set_Size(new System.Drawing.Size(292,
 130));
        this.listView1.set_View(System.Windows.Forms.View.Details);
        this.listView1.set_HideSelection(false);
        // Allow the user to select multiple items.
        this.listView1.set_MultiSelect(true);
        // Show CheckBoxes in the ListView.
        this.listView1.set_CheckBoxes(true);
        //Set the column headers and populate the columns.
        listView1.set_HeaderStyle(ColumnHeaderStyle.Nonclickable);

        ColumnHeader columnHeader1 = new ColumnHeader();
        columnHeader1.set_Text("Breakfast Choices");
        columnHeader1.set_TextAlign(HorizontalAlignment.Left);
        columnHeader1.set_Width(146);

        ColumnHeader columnHeader2 = new ColumnHeader();
        columnHeader2.set_Text("Price Each");
        columnHeader2.set_TextAlign(HorizontalAlignment.Center);
        columnHeader2.set_Width(142);

        this.listView1.get_Columns().Add(columnHeader1);
        this.listView1.get_Columns().Add(columnHeader2);

        String foodList[] = new String[] { "Juice",
 "Coffee", "Cereal & Milk",
            "Fruit Plate", "Toast & Jelly", "Bagel &
 Cream Cheese" };

        String foodPrice[] = new String[] { "1.09",
 "1.09", "2.19", "2.79",
            "2.09", "2.69" };

        int count;
        // Members are added one at a time, so call BeginUpdate to ensure
 
        // the list is painted only once, rather than as each list item
 is added.
        listView1.BeginUpdate();

        for (count = 0; count < foodList.length; count++) {
            ListViewItem listItem =
                new ListViewItem((String)foodList.get_Item(count));
            listItem.get_SubItems().Add((String)foodPrice.get_Item(count));
            listView1.get_Items().Add(listItem);
        }
        //Call EndUpdate when you finish adding items to the ListView.
        listView1.EndUpdate();
        this.get_Controls().Add(this.listView1);
    } //InitializeListView
<br /><span space="preserve">...</span><br /> 
   private double price = 0.0;

    // Handles the ItemCheck event. The method uses the CurrentValue
    // property of the ItemCheckEventArgs to retrieve and tally the
  
    // price of the menu items selected.  
    private void listView1_ItemCheck1(Object
 sender,
        System.Windows.Forms.ItemCheckEventArgs e)
    {
        if (e.get_CurrentValue().Equals(CheckState.Unchecked))
 {
            price += System.Double.Parse(
                this.listView1.get_Items().get_Item(e.get_Index()).
                get_SubItems().get_Item(1).get_Text());
        }
        else {
            if (e.get_CurrentValue().Equals(CheckState.Checked))
 {
                price -= System.Double.Parse(this.listView1.get_Items().
                    get_Item(e.get_Index()).get_SubItems().get_Item(1).
                    get_Text());
            }
        }
        // Output the price to TextBox1.
        textBox1.set_Text(((System.Double)price).ToString());
    } //listView1_ItemCheck1

プラットフォーム

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, 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、1.1、1.0
.NET Compact Framework
サポート対象 : 2.0、1.0

参照

関連項目
ItemCheckEventArgs クラス
ItemCheckEventArgs メンバ
System.Windows.Forms 名前空間
NewValue