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CheckState Enumeration

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)

public enum CheckState

Member nameDescription
Supported by the .NET Compact FrameworkUncheckedThe control is unchecked.
Supported by the .NET Compact FrameworkCheckedThe control is checked.
Supported by the .NET Compact FrameworkIndeterminateThe control is indeterminate. An indeterminate control generally has a shaded appearance.

Multiple methods in CheckBox, CheckedListBox, and ItemCheckEventArgs use this enumeration.

NoteNote:

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.

namespace WindowsApplication1
{
   using System;
   using System.Drawing;
   using System.Collections;
   using System.ComponentModel;
   using System.Windows.Forms;
   using System.Data;
   using System.IO ;

   public class Form1 : 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.Items.AddRange(myFruit);

            // Changes the selection mode from double-click to single click.
         checkedListBox1.CheckOnClick = true;
      }

      protected override void Dispose( bool disposing )
	  {
		if( disposing )
		{
			if (components != null) 
			{
			  components.Dispose();
			}
		}
		base.Dispose( disposing );
	  }

      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.Location = new System.Drawing.Point(144, 64);
         this.textBox1.Size = new System.Drawing.Size(128, 20);
         this.textBox1.TabIndex = 1;
         this.textBox1.TextChanged += new System.EventHandler(this.textBox1_TextChanged);
         this.checkedListBox1.Location = new System.Drawing.Point(16, 64);
         this.checkedListBox1.Size = new System.Drawing.Size(120, 184);
         this.checkedListBox1.TabIndex = 0;
         this.checkedListBox1.ItemCheck += new System.Windows.Forms.ItemCheckEventHandler(this.checkedListBox1_ItemCheck);
         this.listBox1.Location = new System.Drawing.Point(408, 64);
         this.listBox1.Size = new System.Drawing.Size(128, 186);
         this.listBox1.TabIndex = 3;
         this.button1.Enabled = false;
         this.button1.Location = new System.Drawing.Point(144, 104);
         this.button1.Size = new System.Drawing.Size(104, 32);
         this.button1.TabIndex = 2;
         this.button1.Text = "Add Fruit";
         this.button1.Click += new System.EventHandler(this.button1_Click);
         this.button2.Enabled = false;
         this.button2.Location = new System.Drawing.Point(288, 64);
         this.button2.Size = new System.Drawing.Size(104, 32);
         this.button2.TabIndex = 2;
         this.button2.Text = "Show Order";
         this.button2.Click += new System.EventHandler(this.button2_Click);
         this.button3.Enabled = false;
         this.button3.Location = new System.Drawing.Point(288, 104);
         this.button3.Size = new System.Drawing.Size(104, 32);
         this.button3.TabIndex = 2;
         this.button3.Text = "Save Order";
         this.button3.Click += new System.EventHandler(this.button3_Click);
         this.ClientSize = new System.Drawing.Size(563, 273);
         this.Controls.AddRange(new System.Windows.Forms.Control[] {this.listBox1,
                                                        this.button3,
                                                        this.button2,
                                                        this.button1,
                                                        this.textBox1,
                                                        this.checkedListBox1});
         this.Text = "Fruit Order";
      }

      [STAThread]
      public static void Main(string[] args) 
      {
         Application.Run(new Form1());
      }

      // Adds the string if the text box has data in it. 
      private void button1_Click(object sender, System.EventArgs e)
      {
         if(textBox1.Text != "")
         {
            if(checkedListBox1.CheckedItems.Contains(textBox1.Text)== false)
               checkedListBox1.Items.Add(textBox1.Text,CheckState.Checked);
            textBox1.Text = "";
         }

      }
      // Activates or deactivates the Add button. 
      private void textBox1_TextChanged(object sender, System.EventArgs e)
      {
         if (textBox1.Text == "")
         {
            button1.Enabled = false;
         }
         else
         {
            button1.Enabled = true;
         }

        }

      // Moves the checked items from the CheckedListBox to the listBox. 
      private void button2_Click(object sender, System.EventArgs e)
      {
         listBox1.Items.Clear();
         button3.Enabled=false;
         for (int i=0; i< checkedListBox1.CheckedItems.Count;i++)
         {
            listBox1.Items.Add(checkedListBox1.CheckedItems[i]);
         }
         if (listBox1.Items.Count>0)
            button3.Enabled=true;

      }
        // Activates the move button if there are checked items. 
      private void checkedListBox1_ItemCheck(object sender, ItemCheckEventArgs e)
      {
         if(e.NewValue==CheckState.Unchecked)
         {
            if(checkedListBox1.CheckedItems.Count==1)
            {
               button2.Enabled = false;
            }
         }
         else
         {
            button2.Enabled = true;
         }
      }

        // Saves the items to a file. 
      private void button3_Click(object sender, System.EventArgs e)
      {   
         // Insert code to save a file.
         listBox1.Items.Clear();
         IEnumerator myEnumerator;
         myEnumerator = checkedListBox1.CheckedIndices.GetEnumerator();
         int y;
         while (myEnumerator.MoveNext() != false)
         {
            y =(int) myEnumerator.Current;
            checkedListBox1.SetItemChecked(y, false);
         }
         button3.Enabled = false ;
      }        
    }
}

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

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