如何以编程方式复制组合框内容？

Question

I've got this code:

private void FormMain_Shown(object sender, EventArgs e)
{
    ComboBox cmbx;
    foreach (Control C in this.Controls)
    {
        if (C.GetType() == typeof(ComboBox))
        {
            cmbx = C as ComboBox;
            //cmbx.Items.AddRange(cmbxRow0Element0.Items); <= illegal
            object[] obj = new object[cmbxRow0Element0.Items.Count];
            cmbxRow0Element0.Items.CopyTo(obj, 0);
            cmbx.Items.AddRange(obj);
        }
    }
}

...but it doesn't work - I have several combo boxes on a tabPage on a tabControl on a Form, with cmbxRow0Element0 populated with items at design time. The above attempt to copy its items to all the other comboboxes fails, though.

UPDATE

This is the code I now have, and it still doesn't work:

public FormMain()
{
    InitializeComponent();

    for (int i = 0; i < 10; i++)
    {
        this.cmbxRow0Element0.Items.Add(String.Format("Item {0}", i.ToString()));
    }
    foreach (Control C in this.Controls)
    {
        ComboBox cmbx = null;

        // The & test ensures we're not just finding the source combobox
        if ((C.GetType() == typeof(ComboBox)) & ((C as ComboBox) != this.cmbxRow0Element0))
            cmbx = C as ComboBox;
        if (cmbx != null)
        {
            foreach (Object item in cmbxRow0Element0.Items)
            {
                cmbx.Items.Add(item);
            }
        }

    }
}

Perhaps it's something to do with the comboboxes being on tab pages on the tab control?

UPDATE 2

A breakpoint on the first line below is reached, but the second line is never reached:

if ((C.GetType() == typeof(ComboBox)) & ((C as ComboBox) != this.cmbxRow0Element0))
   cmbx = C as ComboBox;

UPDATE 3

The problem was the "find" was not being specific enough - the particular tabPage has to be specified. For more details, see this .

Answer 1

Try this:

var items = cmbxRow0Element0.Items.OfType<object>().ToArray();

foreach (ComboBox c in this.Controls.OfType<ComboBox>())
{
     c.Items.AddRange(items);
}

If you are using tabControl as a container, then it means your comboboxes aren't direct child element of your Form.So you need to access Control collection of the container which is the tabControl . You can do that using this.NameOfYourTabControl.Controls .

Answer 2

A quick test Windows Form app (VS Express 2012) shows this works. In a new blank Windows Form app, drop three (or more) ComboBox controls:

    public Form1()
    {
        InitializeComponent();
        for (int i = 0; i < 10; i++)
        {
            this.comboBox1.Items.Add(String.Format("Item {0}", i.ToString()));
        }
        foreach (Control C in this.Controls)
        {
            ComboBox cmbx = null;

            // The & test ensures we're not just finding the source combobox
            if ((C.GetType() == typeof(ComboBox)) & ((C as ComboBox) != this.comboBox1))
                cmbx = C as ComboBox;
            if (cmbx != null)
            {
                foreach (Object item in comboBox1.Items)
                {
                    cmbx.Items.Add(item);
                }
            }

        }
    }