CheckState Enumeration
.NET Framework 2.0
Specifies the state of a control, such as a check box, that can be checked, unchecked, or set to an indeterminate state.
Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in system.windows.forms.dll)
Assembly: System.Windows.Forms (in system.windows.forms.dll)
Multiple methods in CheckBox, CheckedListBox, and ItemCheckEventArgs use this enumeration.
Note |
|---|
| Use an indeterminately checked control when you do not want to set a default value. |
The following code example demonstrates the use of the CheckState enumeration.
Option Explicit Option Strict Imports System Imports System.Drawing Imports System.Collections Imports System.ComponentModel Imports System.Windows.Forms Imports System.Data Imports System.IO Namespace WindowsApplication1 Public Class Form1 Inherits System.Windows.Forms.Form Private WithEvents checkedListBox1 As System.Windows.Forms.CheckedListBox Private WithEvents textBox1 As System.Windows.Forms.TextBox Private WithEvents button1 As System.Windows.Forms.Button Private WithEvents button2 As System.Windows.Forms.Button Private WithEvents listBox1 As System.Windows.Forms.ListBox Private WithEvents button3 As System.Windows.Forms.Button Private components As System.ComponentModel.Container Public Sub New() InitializeComponent() ' Sets up the initial objects in the CheckedListBox. Dim myFruit As String() = {"Apples", "Oranges", "Tomato"} checkedListBox1.Items.AddRange(myFruit) ' Changes the selection mode from double-click to single click. checkedListBox1.CheckOnClick = True End Sub 'New Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean) If disposing Then If Not (components Is Nothing) Then components.Dispose() End If End If MyBase.Dispose(disposing) End Sub Private Sub InitializeComponent() Me.components = New System.ComponentModel.Container() Me.textBox1 = New System.Windows.Forms.TextBox() Me.checkedListBox1 = New System.Windows.Forms.CheckedListBox() Me.listBox1 = New System.Windows.Forms.ListBox() Me.button1 = New System.Windows.Forms.Button() Me.button2 = New System.Windows.Forms.Button() Me.button3 = New System.Windows.Forms.Button() Me.textBox1.Location = New System.Drawing.Point(144, 64) Me.textBox1.Size = New System.Drawing.Size(128, 20) Me.textBox1.TabIndex = 1 Me.checkedListBox1.Location = New System.Drawing.Point(16, 64) Me.checkedListBox1.Size = New System.Drawing.Size(120, 184) Me.checkedListBox1.TabIndex = 0 Me.listBox1.Location = New System.Drawing.Point(408, 64) Me.listBox1.Size = New System.Drawing.Size(128, 186) Me.listBox1.TabIndex = 3 Me.button1.Enabled = False Me.button1.Location = New System.Drawing.Point(144, 104) Me.button1.Size = New System.Drawing.Size(104, 32) Me.button1.TabIndex = 2 Me.button1.Text = "Add Fruit" Me.button2.Enabled = False Me.button2.Location = New System.Drawing.Point(288, 64) Me.button2.Size = New System.Drawing.Size(104, 32) Me.button2.TabIndex = 2 Me.button2.Text = "Show Order" Me.button3.Enabled = False Me.button3.Location = New System.Drawing.Point(288, 104) Me.button3.Size = New System.Drawing.Size(104, 32) Me.button3.TabIndex = 2 Me.button3.Text = "Save Order" Me.ClientSize = New System.Drawing.Size(563, 273) Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.listBox1, Me.button3, Me.button2, Me.button1, Me.textBox1, Me.checkedListBox1}) Me.Text = "Fruit Order" End Sub 'InitializeComponent <STAThread()> _ Public Shared Sub Main() Application.Run(New Form1()) End Sub 'Main ' Adds the string if the text box has data in it. Private Sub button1_Click(sender As Object, _ e As System.EventArgs) Handles button1.Click If textBox1.Text <> "" Then If checkedListBox1.CheckedItems.Contains(textBox1.Text) = False Then checkedListBox1.Items.Add(textBox1.Text, CheckState.Checked) End If textBox1.Text = "" End If End Sub 'button1_Click ' Activates or deactivates the Add button. Private Sub textBox1_TextChanged(sender As Object, _ e As System.EventArgs) Handles textBox1.TextChanged If textBox1.Text = "" Then button1.Enabled = False Else button1.Enabled = True End If End Sub 'textBox1_TextChanged ' Moves the checked items from the CheckedListBox to the listBox. Private Sub button2_Click(sender As Object, _ e As System.EventArgs) Handles button2.Click listBox1.Items.Clear() button3.Enabled = False Dim i As Integer For i = 0 To checkedListBox1.CheckedItems.Count - 1 listBox1.Items.Add(checkedListBox1.CheckedItems(i)) Next i If listBox1.Items.Count > 0 Then button3.Enabled = True End If End Sub 'button2_Click ' Activates the move button if there are checked items. Private Sub checkedListBox1_ItemCheck(sender As Object, _ e As ItemCheckEventArgs) Handles checkedListBox1.ItemCheck If e.NewValue = CheckState.Unchecked Then If checkedListBox1.CheckedItems.Count = 1 Then button2.Enabled = False End If Else button2.Enabled = True End If End Sub 'checkedListBox1_ItemCheck ' Saves the items to a file. Private Sub button3_Click(sender As Object, _ e As System.EventArgs) Handles button3.Click ' Insert code to save a file. listBox1.Items.Clear() Dim myEnumerator As IEnumerator myEnumerator = checkedListBox1.CheckedIndices.GetEnumerator() Dim y As Integer While myEnumerator.MoveNext() <> False y = CInt(myEnumerator.Current) checkedListBox1.SetItemChecked(y, False) End While button3.Enabled = False End Sub 'button3_Click End Class 'Form1 End Namespace 'WindowsApplication1
import System.*;
import System.Drawing.*;
import System.Collections.*;
import System.ComponentModel.*;
import System.Windows.Forms.*;
import System.Data.*;
import System.IO.*;
public class Form1 extends System.Windows.Forms.Form
{
private System.Windows.Forms.CheckedListBox checkedListBox1;
private System.Windows.Forms.TextBox textBox1;
private System.Windows.Forms.Button button1;
private System.Windows.Forms.Button button2;
private System.Windows.Forms.ListBox listBox1;
private System.Windows.Forms.Button button3;
private System.ComponentModel.Container components;
public Form1()
{
InitializeComponent();
// Sets up the initial objects in the CheckedListBox.
String myFruit[] = { "Apples", "Oranges", "Tomato" };
checkedListBox1.get_Items().AddRange(myFruit);
// Changes the selection mode from double-click to single click.
checkedListBox1.set_CheckOnClick(true);
} //Form1
protected void Dispose(boolean disposing)
{
if (disposing) {
if (components != null) {
components.Dispose();
}
}
super.Dispose(disposing);
} //Dispose
private void InitializeComponent()
{
this.components = new System.ComponentModel.Container();
this.textBox1 = new System.Windows.Forms.TextBox();
this.checkedListBox1 = new System.Windows.Forms.CheckedListBox();
this.listBox1 = new System.Windows.Forms.ListBox();
this.button1 = new System.Windows.Forms.Button();
this.button2 = new System.Windows.Forms.Button();
this.button3 = new System.Windows.Forms.Button();
this.textBox1.set_Location(new System.Drawing.Point(144, 64));
this.textBox1.set_Size(new System.Drawing.Size(128, 20));
this.textBox1.set_TabIndex(1);
this.textBox1.add_TextChanged(new System.EventHandler(
this.textBox1_TextChanged));
this.checkedListBox1.set_Location(new System.Drawing.Point(16, 64));
this.checkedListBox1.set_Size(new System.Drawing.Size(120, 184));
this.checkedListBox1.set_TabIndex(0);
this.checkedListBox1.add_ItemCheck(
new System.Windows.Forms.ItemCheckEventHandler(
this.checkedListBox1_ItemCheck));
this.listBox1.set_Location(new System.Drawing.Point(408, 64));
this.listBox1.set_Size(new System.Drawing.Size(128, 186));
this.listBox1.set_TabIndex(3);
this.button1.set_Enabled(false);
this.button1.set_Location(new System.Drawing.Point(144, 104));
this.button1.set_Size(new System.Drawing.Size(104, 32));
this.button1.set_TabIndex(2);
this.button1.set_Text("Add Fruit");
this.button1.add_Click(new System.EventHandler(this.button1_Click));
this.button2.set_Enabled(false);
this.button2.set_Location(new System.Drawing.Point(288, 64));
this.button2.set_Size(new System.Drawing.Size(104, 32));
this.button2.set_TabIndex(2);
this.button2.set_Text("Show Order");
this.button2.add_Click(new System.EventHandler(this.button2_Click));
this.button3.set_Enabled(false);
this.button3.set_Location(new System.Drawing.Point(288, 104));
this.button3.set_Size(new System.Drawing.Size(104, 32));
this.button3.set_TabIndex(2);
this.button3.set_Text("Save Order");
this.button3.add_Click(new System.EventHandler(this.button3_Click));
this.set_ClientSize(new System.Drawing.Size(563, 273));
this.get_Controls().AddRange(new System.Windows.Forms.Control[] {
this.listBox1, this.button3, this.button2, this.button1,
this.textBox1, this.checkedListBox1});
this.set_Text("Fruit Order");
} //InitializeComponent
/** @attribute STAThread()
*/
public static void main(String[] args)
{
Application.Run(new Form1());
} //main
// Adds the string if the text box has data in it.
private void button1_Click(Object sender, System.EventArgs e)
{
if (!textBox1.get_Text().Equals("")) {
if (checkedListBox1.get_CheckedItems().Contains(textBox1.get_Text())
== false) {
checkedListBox1.get_Items().Add(textBox1.get_Text(),
CheckState.Checked);
}
textBox1.set_Text("");
}
} //button1_Click
// Activates or deactivates the Add button.
private void textBox1_TextChanged(Object sender, System.EventArgs e)
{
if (textBox1.get_Text().Equals("")) {
button1.set_Enabled(false);
}
else {
button1.set_Enabled(true);
}
} //textBox1_TextChanged
// Moves the checked items from the CheckedListBox to the listBox.
private void button2_Click(Object sender, System.EventArgs e)
{
listBox1.get_Items().Clear();
button3.set_Enabled(false);
for (int i = 0; i < checkedListBox1.get_CheckedItems().get_Count();
i++) {
listBox1.get_Items().Add(
checkedListBox1.get_CheckedItems().get_Item(i));
}
if (listBox1.get_Items().get_Count() > 0) {
button3.set_Enabled(true);
}
} //button2_Click
// Activates the move button if there are checked items.
private void checkedListBox1_ItemCheck(Object sender, ItemCheckEventArgs e)
{
if (e.get_NewValue().Equals(CheckState.Unchecked)) {
if (checkedListBox1.get_CheckedItems().get_Count() == 1) {
button2.set_Enabled(false);
}
}
else {
button2.set_Enabled(true);
}
} //checkedListBox1_ItemCheck
// Saves the items to a file.
private void button3_Click(Object sender, System.EventArgs e)
{
// Insert code to save a file.
listBox1.get_Items().Clear();
IEnumerator myEnumerator;
myEnumerator = checkedListBox1.get_CheckedIndices().GetEnumerator();
int y;
while ((myEnumerator.MoveNext() != false)) {
y = (int)(System.Convert.ToInt32(myEnumerator.get_Current()));
checkedListBox1.SetItemChecked(y, false);
}
button3.set_Enabled(false);
} //button3_Click
} //Form1
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
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.
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