ComboBox.ObjectCollection.RemoveAt メソッド
ComboBox 内の指定したインデックス位置の項目を削除します。 名前空間: System.Windows.Forms
アセンブリ: System.Windows.Forms (system.windows.forms.dll 内)
構文
例外
使用例
プラットフォーム
バージョン情報
参照
アセンブリ: System.Windows.Forms (system.windows.forms.dll 内)
構文例外使用例MaxDropDownItems プロパティと DropDownStyle プロパティを設定し、ComboBox を検索する FindStringExact メソッドと ComboBox から項目を削除する RemoveAt メソッドを使用して、ComboBox コントロールを初期化する方法を次のコード例に示します。この例はまた、SelectedIndexChanged イベントの処理方法も示しています。この例を実行するには、TextBox1 という名前の TextBox オブジェクトが配置されているフォームに次のコードを貼り付けて、フォームのコンストラクタまたは Load メソッドから InitializeComboBox メソッドを呼び出します。
' Declare comboBox1 as a ComboBox.
Friend WithEvents ComboBox1 As
System.Windows.Forms.ComboBox
' This method initializes the combo box, adding a large string
' array but limiting the drop-down size to six rows so the combo
box
' doesn't cover other controls when it expands.
Private Sub InitializeComboBox()
Me.ComboBox1 = New System.Windows.Forms.ComboBox
Dim employees() As String
= New String() {"Hamilton,
David", _
"Hensien, Kari", "Hammond,
Maria", "Harris, Keith", _
"Henshaw, Jeff D.", "Hanson,
Mark", "Harnpadoungsataya, Sariya",
_
"Harrington, Mark", "Harris,
Keith", "Hartwig, Doris", _
"Harui, Roger", "Hassall,
Mark", "Hasselberg, Jonas", _
"Harnpadoungsataya, Sariya", "Henshaw,
Jeff D.", "Henshaw, Jeff D.", _
"Hensien, Kari", "Harris,
Keith", "Henshaw, Jeff D.", _
"Hensien, Kari", "Hasselberg,
Jonas", "Harrington, Mark", _
"Hedlund, Magnus", "Hay,
Jeff", "Heidepriem, Brandon D."}
ComboBox1.Items.AddRange(employees)
Me.ComboBox1.Location = New System.Drawing.Point(136,
32)
Me.ComboBox1.MaxDropDownItems = 5
Me.ComboBox1.DropDownStyle = ComboBoxStyle.DropDown
Me.ComboBox1.Name = "ComboBox1"
Me.ComboBox1.Size = New System.Drawing.Size(136,
81)
Me.ComboBox1.TabIndex = 0
Me.Controls.Add(Me.ComboBox1)
End Sub
<br /><span space="preserve">...</span><br
/> ' This method is called when the user changes his or her
selection.
' It searches for all occurrences of the selected employee's
' name in the Items array and adds the employee's name and
' the number of occurrences to TextBox1.Text.
' CAUTION This code exposes a known bug: If the index passed to
the
' FindStringExact(searchString, index) method is the last index
' of the array, the code throws an exception.
Private Sub ComboBox1_SelectedIndexChanged(ByVal
sender As Object, _
ByVal e As System.EventArgs) Handles
ComboBox1.SelectedIndexChanged
Dim comboBox As comboBox = CType(sender,
comboBox)
' Save the selected employee's name, because we will remove
' the employee's name from the list.
Dim selectedEmployee = CType(ComboBox1.SelectedItem, String)
Dim count As Integer
= 0
Dim resultIndex As Integer
= -1
' Call the FindStringExact method to find the first
' occurrence in the list.
resultIndex = ComboBox1.FindStringExact(ComboBox1.SelectedItem)
' Remove the name as it is found, and increment the found count.
' Then call the FindStringExact method again, passing in the
index of the
' current found item so the search starts there instead of
' at the beginning of the list.
While (resultIndex <> -1)
ComboBox1.Items.RemoveAt(resultIndex)
count += 1
resultIndex = ComboBox1.FindStringExact _
(selectedEmployee, resultIndex)
End While
' Update the text in Textbox1.
TextBox1.Text = TextBox1.Text & Microsoft.VisualBasic.vbCrLf _
& selectedEmployee & ": " &
count
End Sub
// Declare comboBox1 as a ComboBox. internal System.Windows.Forms.ComboBox ComboBox1; // This method initializes the combo box, adding a large string array // but limiting the drop-down size to six rows so the combo box doesn't // cover other controls when it expands. private void InitializeComboBox() { this.ComboBox1 = new System.Windows.Forms.ComboBox(); string[] employees = new string[]{"Hamilton, David", "Hensien, Kari", "Hammond, Maria", "Harris, Keith", "Henshaw, Jeff D.", "Hanson, Mark", "Harnpadoungsataya, Sariya", "Harrington, Mark", "Harris, Keith", "Hartwig, Doris", "Harui, Roger", "Hassall, Mark", "Hasselberg, Jonas", "Harnpadoungsataya, Sariya", "Henshaw, Jeff D.", "Henshaw, Jeff D.", "Hensien, Kari", "Harris, Keith", "Henshaw, Jeff D.", "Hensien, Kari", "Hasselberg, Jonas", "Harrington, Mark", "Hedlund, Magnus", "Hay, Jeff", "Heidepriem, Brandon D."}; ComboBox1.Items.AddRange(employees); this.ComboBox1.Location = new System.Drawing.Point(136, 32); this.ComboBox1.MaxDropDownItems = 5; this.ComboBox1.DropDownStyle = ComboBoxStyle.DropDownList; this.ComboBox1.Name = "ComboBox1"; this.ComboBox1.Size = new System.Drawing.Size(136, 81); this.ComboBox1.TabIndex = 0; this.Controls.Add(this.ComboBox1); // Associate the event-handling method with the // SelectedIndexChanged event. this.ComboBox1.SelectedIndexChanged += new System.EventHandler(ComboBox1_SelectedIndexChanged); } <br /><span space="preserve">...</span><br /> // This method is called when the user changes his or her selection. // It searches for all occurrences of the selected employee's // name in the Items array and adds the employee's name and // the number of occurrences to TextBox1.Text. // CAUTION This code exposes a known bug: If the index passed to the // FindStringExact(searchString, index) method is the last index // of the array, the code throws an exception. private void ComboBox1_SelectedIndexChanged(object sender, System.EventArgs e) { ComboBox comboBox = (ComboBox) sender; // Save the selected employee's name, because we will remove // the employee's name from the list. string selectedEmployee = (string) ComboBox1.SelectedItem; int count = 0; int resultIndex = -1; // Call the FindStringExact method to find the first // occurrence in the list. resultIndex = ComboBox1.FindStringExact(selectedEmployee); // Remove the name as it is found, and increment the found count. // Then call the FindStringExact method again, passing in the // index of the current found item so the search starts there // instead of at the beginning of the list. while (resultIndex!=-1) { ComboBox1.Items.RemoveAt(resultIndex); count += 1; resultIndex = ComboBox1.FindStringExact(selectedEmployee, resultIndex); } // Update the text in Textbox1. TextBox1.Text = TextBox1.Text+ "\r\n" + selectedEmployee + ": " + count; }
// Declare comboBox1 as a ComboBox. internal: System::Windows::Forms::ComboBox^ ComboBox1; private: // This method initializes the combo box, adding a large string array // but limiting the drop-down size to six rows so the combo box doesn't // cover other controls when it expands. void InitializeComboBox() { this->ComboBox1 = gcnew System::Windows::Forms::ComboBox; array<String^>^ employees = {"Hamilton, David","Hensien, Kari", "Hammond, Maria","Harris, Keith","Henshaw, Jeff D.", "Hanson, Mark","Harnpadoungsataya, Sariya", "Harrington, Mark","Harris, Keith","Hartwig, Doris" , "Harui, Roger","Hassall, Mark","Hasselberg, Jonas" , "Harnpadoungsataya, Sariya","Henshaw, Jeff D.", "Henshaw, Jeff D.","Hensien, Kari","Harris, Keith" , "Henshaw, Jeff D.","Hensien, Kari","Hasselberg, Jonas", "Harrington, Mark","Hedlund, Magnus","Hay, Jeff" , "Heidepriem, Brandon D."}; ComboBox1->Items->AddRange( employees ); this->ComboBox1->Location = System::Drawing::Point( 136, 32 ); this->ComboBox1->MaxDropDownItems = 5; this->ComboBox1->DropDownStyle = ComboBoxStyle::DropDownList; this->ComboBox1->Name = "ComboBox1"; this->ComboBox1->Size = System::Drawing::Size( 136, 81 ); this->ComboBox1->TabIndex = 0; this->Controls->Add( this->ComboBox1 ); // Associate the event-handling method with the // SelectedIndexChanged event. this->ComboBox1->SelectedIndexChanged += gcnew System::EventHandler( this, &Form1::ComboBox1_SelectedIndexChanged ); } <br /><span space="preserve">...</span><br />private: // This method is called when the user changes his or her selection. // It searches for all occurrences of the selected employee's // name in the Items array and adds the employee's name and // the number of occurrences to TextBox1.Text. // CAUTION This code exposes a known bug: If the index passed to the // FindStringExact(searchString, index) method is the last index // of the array, the code throws an exception. void ComboBox1_SelectedIndexChanged( Object^ sender, System::EventArgs^ e ) { ComboBox^ comboBox = (ComboBox^)(sender); // Save the selected employee's name, because we will remove // the employee's name from the list. String^ selectedEmployee = (String^)(ComboBox1->SelectedItem); int count = 0; int resultIndex = -1; // Call the FindStringExact method to find the first // occurrence in the list. resultIndex = ComboBox1->FindStringExact( selectedEmployee ); // Remove the name as it is found, and increment the found count. // Then call the FindStringExact method again, passing in the // index of the current found item so the search starts there // instead of at the beginning of the list. while ( resultIndex != -1 ) { ComboBox1->Items->RemoveAt( resultIndex ); count += 1; resultIndex = ComboBox1->FindStringExact( selectedEmployee, resultIndex ); } TextBox1->Text = TextBox1->Text + "\r\n" + selectedEmployee + ": " + count; }
// Declare comboBox1 as a ComboBox. System.Windows.Forms.ComboBox comboBox1; // This method initializes the combo box, adding a large string array // but limiting the drop-down size to six rows so the combo box doesn't // cover other controls when it expands. private void InitializeComboBox() { this.comboBox1 = new System.Windows.Forms.ComboBox(); String employees[] = new String[] { "Hamilton, David", "Hensien, Kari", "Hammond, Maria", "Harris, Keith", "Henshaw, Jeff D.", "Hanson, Mark", "Harnpadoungsataya, Sariya", "Harrington, Mark", "Harris, Keith", "Hartwig, Doris", "Harui, Roger", "Hassall, Mark", "Hasselberg, Jonas", "Harnpadoungsataya, Sariya", "Henshaw, Jeff D.","Henshaw, Jeff D.", "Hensien, Kari", "Harris, Keith", "Henshaw, Jeff D.", "Hensien, Kari", "Hasselberg, Jonas", "Harrington, Mark", "Hedlund, Magnus", "Hay, Jeff", "Heidepriem, Brandon D." }; comboBox1.get_Items().AddRange(employees); this.comboBox1.set_Location(new System.Drawing.Point(136, 32)); this.comboBox1.set_MaxDropDownItems(5); this.comboBox1.set_DropDownStyle(ComboBoxStyle.DropDownList); this.comboBox1.set_Name("comboBox1"); this.comboBox1.set_Size(new System.Drawing.Size(136, 81)); this.comboBox1.set_TabIndex(0); this.get_Controls().Add(this.comboBox1); // Associate the event-handling method with the // SelectedIndexChanged event. this.comboBox1.add_SelectedIndexChanged(new System.EventHandler( comboBox1_SelectedIndexChanged)); } //InitializeComboBox <br /><span space="preserve">...</span><br /> // This method is called when the user changes his or her selection. // It searches for all occurrences of the selected employee's // name in the Items array and adds the employee's name and // the number of occurrences to textBox1.Text. // CAUTION This code exposes a known bug: If the index passed to the // FindStringExact(searchString, index) method is the last index // of the array, the code throws an exception. private void comboBox1_SelectedIndexChanged(Object sender, System.EventArgs e) { ComboBox comboBox = (ComboBox)sender; // Save the selected employee's name, because we will remove // the employee's name from the list. String selectedEmployee = (String)(comboBox1.get_SelectedItem()); int count = 0; int resultIndex = -1; // Call the FindStringExact method to find the first // occurrence in the list. resultIndex = comboBox1.FindStringExact(selectedEmployee); // Remove the name as it is found, and increment the found count. // Then call the FindStringExact method again, passing in the // index of the current found item so the search starts there // instead of at the beginning of the list. while (resultIndex != -1) { comboBox1.get_Items().RemoveAt(resultIndex); count += 1; resultIndex = comboBox1.FindStringExact(selectedEmployee, resultIndex); } // Update the text in textBox1. textBox1.set_Text(textBox1.get_Text() + "\r\n" + selectedEmployee + ": " + count); } //comboBox1_SelectedIndexChanged
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。
バージョン情報参照- ComboBox.ObjectCollection.RemoveAt メソッドのページへのリンク
