如何防止组合框SelectedIndexChanged触发？

Question

In two words I want to return the previous selecteditem without selecting it again or without triggering the SelectedIndexChanged method.

This is the situation: I have combo box and when a item is selected, datagridview is filled with rows. You can edit things in the datagridview and save them to a file. If you don't save the changes and try to change the item in the combo box it tells you that all the changes will be lost. I make a messagebox that make you choose between yes(to change) and no(not to change). If you click yes everything is OK, but if you click NO then I have to return the previous selected item. When I do so I trigger SelectedIndexChanged and that makes the datagridview load again and delete the changes. Here is my code in the SelectedIndexChanged method:

if (!ChangeMade)
        {
           //#1 Some Code
         }
else
        {
            DialogResult dialogResult =
            MessageBox.Show("Are you sure you want to change the manifacturer?" +
                            "\n    All the changes you have done will be lost.",
            "Warning", MessageBoxButtons.YesNo);

            if (dialogResult == DialogResult.Yes)
            {
              //same code as #1                
            }
            else
            {
               //Here must be the code that returns the previous 
               //item without selecting it.
            }

Sorry for my english.

Answer 1

As I see it you want to change data only when user changes combo box. For this scenario SelectionChangeCommitted is perfect because it only triggers when user makes changes to combobox .

private void TypeSelectionChangeCommitted(object sender, EventArgs e)
{
    if (!ChangeMade)
    {
       //#1 Some Code
    }
    else
    {
        DialogResult dialogResult =
        MessageBox.Show("Are you sure you want to change the manifacturer?" +
                        "\n    All the changes you have done will be lost.",
        "Warning", MessageBoxButtons.YesNo);

        if (dialogResult == DialogResult.Yes)
        {
          //same code as #1                
        }
        else
        {
           //Here must be the code that returns the previous 
           //item without selecting it.
        }
    }
}

More info on MSDN

Answer 2

The way I do this:

private void ComboBoxOnChange(...)
{
    if (!shouldTrigger)
        return;

    shouldTrigger = true;
    // Here goes your code
    should trigger = false;
}

Answer 3

  this.comboBox1.SelectedIndexChanged -= new EventHandler(comboBox1_SelectedIndexChanged);