How do I know which combobox is selected?

Question

I have a windowsform with a datagridview. The datagridview has 3 comboboxes.

When I select a combobox and change the value there must something happen.

The problem is that I don't know how I can tell whicht combobox is selected.

I have the followingcode:

private void NaardataGridView2_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)

{

   //here we will add the combo box's selected event changed ComboBox cmbBox;

  if (NaardataGridView2.CurrentCell.ColumnIndex == 0)

  {

        cmbBox = e.Control as ComboBox;

         if (cmbBox == null) { return; }

        cmbBox.SelectedIndexChanged += cmbBox_SelectedIndexChanged;

  }

  }

void cmbBox_SelectedIndexChanged(object sender, EventArgs e)

{

int rowNr = NaardataGridView2.CurrentRow.Index;

ComboBox cmbBox = (ComboBox)sender;

NaardataGridView2.Rows[rowNr].Cells[4].Value = Convert.ToString(cmbBox.SelectedIndex);

}

 

before it does --> NaardataGridView2.Rows[rowNr].Cells[4].Value = Convert.ToString(cmbBox.SelectedIndex);

I want to know which combobox is selected, how can I do this?

This code doesn't work because the name is empty--> if (Convert.ToString(cmbBox.Name) == "ab") {}

Does some one know what I do wrong?

Answer 1

You're almost there - the sender argument is [a reference to] the ComboBox that raised the event so you just need to somehow identify each one. 

How did(?) you create these ComboBoxes?  If you used a Designer, then that should give you an opportunity to assign each one a meaningful name, which you can retrieve this through the sender reference. 

If they're being added in code (and, let's face it, everything is these days; you just have to find the code), simply assign each a meaningful name as it's created.

---

Regards, Phill W.

Answer 2

The comboboxes are created by code. I also gave them a name, but that is just the problem the following code doesn't work:

string whichBox = cmbBox.Name;

 

This gives me a empty string.

Answer 3

Compare the values of GetHashCode() for the ComboBoxes you create and those coming through the sender reference. 

They should be the same but I suspect your events are being sent some other ComboBoxes. 

 

---

Regards, Phill W.

Answer 4

I'm still a junior programmer, can you give me some code how to do your solution?

Answer 5

When you create your Comboxes, add something like this:

using System.Diagnostics; 
using System.Windows.Forms; 

ComboBox thing = new ComboBox(); 
Debug.WriteLine( "Created " + thing.GetHashCode().ToString() ); 

Then, in your event handler(s):

Debug.WriteLine( "Recevied " + sender.GetHashCode().ToString() ); 

The values you see in the event handler(s) should match [one of] those you see as you create the Controls.  If not, then something's getting in the way and "substituting" your Controls with new ones.

---

Regards, Phill W.