如何以编程方式检查C＃中CheckedListBox中的项？

Question

I have a CheckedListBox, and I want to automatically tick one of the items in it.

The CheckedItems collection doesn't allow you to add things to it.

Any suggestions?

Answer 1

You need to call SetItemChecked with the relevant item.

The documentation for CheckedListBox.ObjectCollection has an example which checks every other item in a collection.

Answer 2

This is how you can select/tick or deselect/untick all of the items at once:

private void SelectAllCheckBoxes(bool CheckThem) {
    for (int i = 0; i <= (checkedListBox1.Items.Count - 1); i++) {
        if (CheckThem)
        {
            checkedListBox1.SetItemCheckState(i, CheckState.Checked);
        }
        else
        {
            checkedListBox1.SetItemCheckState(i, CheckState.Unchecked);
        }
    }  
}

Answer 3

In my program I've used the following trick:

CheckedListBox.SetItemChecked(CheckedListBox.Items.IndexOf(Item),true);

How does things works:
SetItemChecked(int index, bool value) is method which sets the exact checked state at the specific item. You have to specify index of item You want to check ( use IndexOf method, as an argument specify text of item ) and checked state ( true means item is checked, false unchecked ).
This method runs through all items in CheckedListBox and checks ( or unchecks ) the one with specified index.
For example, a short piece of my code - FOREACH cycle runs through specified program names, and if the program is contained in CheckedLitBox ( CLB... ), checks it:

string[] ProgramNames = sel_item.SubItems[2].Text.Split(';');
foreach (string Program in ProgramNames)
{
    if (edit_mux.CLB_ContainedPrograms.Items.Contains(Program))
        edit_mux.CLB_ContainedPrograms.SetItemChecked(edit_mux.CLB_ContainedPrograms.Items.IndexOf(Program), true);
}

Answer 4

Suppose you want to check the item on clicking a button.

private void button1_Click(object sender, EventArgs e)
{
    checkedListBox1.SetItemChecked(itemIndex, true);
}

Where itemIndex is the index of the item to be checked, it starts from 0.

Answer 5

Use:

string[] aa = new string[] {"adiii", "yaseen", "salman"};
foreach (string a in aa)
{
    checkedListBox1.Items.Add(a);
}

Now code where you want to check all:

private void button5_Click(object sender, EventArgs e)
{
    for(int a=0; a<checkedListBox1.Items.Count; a++)
        checkedListBox1.SetItemChecked(a, true);
}

To uncheck all:

private void button_Click(object sender, EventArgs e)
{
    for(int a=0; a<checkedListBox1.Items.Count; a++)
        checkedListBox1.SetItemChecked(a, false);
}

Answer 6

I use an extension:

public static class CheckedListBoxExtension
{
    public static void CheckAll(this CheckedListBox listbox)
    {
        Check(listbox, true);
    }

    public static void UncheckAll(this CheckedListBox listbox)
    {
        Check(listbox, false);
    }

    private static void Check(this CheckedListBox listbox, bool check)
    {
        Enumerable.Range(0, listbox.Items.Count).ToList().ForEach(x => listbox.SetItemChecked(x, check));
    }
}