C#

private void column1DataGridViewComboBox_SelectedIndexChanged(object sender, EventArgs e)
        {

            ComboBox cb = sender as ComboBox;

         
            string strPrimary = cb.SelectedItem.ToString();
            Debug.WriteLine(strPrimary);

            var dataSource = new List<Units>();

            switch (strPrimary)
            {
                case "1":
                    
                //Build a list 
                
                dataSource.Add(new Units() { Unit = "blah1" });
                dataSource.Add(new Units() { Unit = "blah2" });
                dataSource.Add(new Units() { Unit = "blah3" });

                //Setup data binding 
                this.column2DataGridViewComboBox.DataSource = dataSource;
                this.column2DataGridViewComboBox.DisplayMember = "Unit";

                break;

                case "2":

                //Build a list 
                dataSource.Add(new Units() { Unit = "blah4" });
                dataSource.Add(new Units() { Unit = "blah5" });
                dataSource.Add(new Units() { Unit = "blah6" });

                //Setup data binding 
                this.column2DataGridViewComboBox.DataSource = dataSource;
                this.column2DataGridViewComboBox.DisplayMember = "Unit";

                break;

                case "3":

                //Build a list 
                dataSource.Add(new Units() { Unit = "blah7" });
                dataSource.Add(new Units() { Unit = "blah8" });
                dataSource.Add(new Units() { Unit = "blah9" });

                //Setup data binding 
                this.column2DataGridViewComboBox.DataSource = dataSource;
                this.column2DataGridViewComboBox.DisplayMember = "Unit";

                break;

            }
        }<pre>

Well, the problem of course as you know is that ComboBox cb points to the second comboBox once I select it.  In fact, once I select a value on the first comboBox and then select the second comboBox to select a value, debug.writeline gives me "WindowsFormsApplication1.Form1+Units" (although the 2nd comboBox does get populated with the appropriate list based upon the selection of the first comboBox).  If I use an integer instead of strPrimary and set it as cb.SelectedIndex, what I actually get from debug is the index of the selection of the list of the second comboBox (eg if blah5 is selected, I get an integer = 1) followed by an integer = 0 (I don't know why it is passing that second integer = 0  ??), which then causes the list to be regenerated to the items in case 0.  Since ComboBox cb points to the second comboBox, and it passes that second integer = 0, the only allowable entry into the second comboBox would be "blah1"

With all of this, it seems that either close or going about it all wrong, but I don't know enough to make that call.  I know that the control for each comboBox needs to be separated, but don't have the slightest notion how to do that.  You had mentioned that in a previous post, but in the EditingControlShowing handler.  As usual, any suggestions would be greatly appreciated.

private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
   ComboBox cb;

   // switch (dataGrid.CurrentCell.ColumnIndex)   <===================================== silly! already have column in eventargs
   switch (e.Column)                              //<==============================Use this instead
   {
       case 0:  // use the index for your comboboxcolumn    <============ <big>V IMPORTANT</big> make sure that the 0: matches the index for your column
           cb = e.Control as ComboBox;
           if (cb != null)
           {
           // first remove event handler to keep from attaching multiple:
           cb.SelectedIndexChanged -= column1DataGridViewComboBox_SelectedIndexChanged;
           // now attach the event handler
           cb.SelectedIndexChanged += column1DataGridViewComboBox_SelectedIndexChanged;
           }
           break;
        // <================================== You do not need the part below since you only need it to apply to the first cbcolumn
      //case 3: // use the index for your second combo
        //   cb = e.Control as ComboBox;
          // if (cb != null)
           //{
           // first remove event handler to keep from attaching multiple:
         //  cb.SelectedIndexChanged -= cb_SecondSelectedIndexChanged;
           // now attach the event handler
          // cb.SelectedIndexChanged += cb_SecondSelectedIndexChanged;
           //}
           //break;
   }
}

private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
   ComboBox cb;

   // replace the switch statement by an if statement
   if (e.Column == 0)  //<============ <big>V IMPORTANT</big> change the 0 (if necessary) to  match the index for your column
   {
           cb = e.Control as ComboBox;
           if (cb != null)
           {
           // first remove event handler to keep from attaching multiple:
           cb.SelectedIndexChanged -= column1DataGridViewComboBox_SelectedIndexChanged;
           // now attach the event handler
           cb.SelectedIndexChanged += column1DataGridViewComboBox_SelectedIndexChanged;
           }
    }
}

private void column1DataGridViewComboBox_SelectedIndexChanged(object sender, EventArgs e)
        {

            
            ComboBox cb = sender as ComboBox;

          
            int intPrimary = cb.SelectedIndex;
            Debug.WriteLine(intPrimary + "SelectedIndexChanged");

            var dataSource = new List<Units>();

            switch (intPrimary)
            {
                case 0:
                    
                //Build a list 
                
                dataSource.Add(new Units() { Unit = "blah1" });
                dataSource.Add(new Units() { Unit = "blah2" });
                dataSource.Add(new Units() { Unit = "blah3" });

                //Setup data binding 
                this.column2DataGridViewComboBox.DataSource = dataSource;
                this.column2DataGridViewComboBox.DisplayMember = "Unit";

                break;

                case 1:

                //Build a list 
                dataSource.Add(new Units() { Unit = "blah4" });
                dataSource.Add(new Units() { Unit = "blah5" });
                dataSource.Add(new Units() { Unit = "blah6" });

                //Setup data binding 
                this.column2DataGridViewComboBox.DataSource = dataSource;
                this.column2DataGridViewComboBox.DisplayMember = "Unit";

                break;

                case 2:

                //Build a list 
                dataSource.Add(new Units() { Unit = "blah7" });
                dataSource.Add(new Units() { Unit = "blah8" });
                dataSource.Add(new Units() { Unit = "blah9" });

                //Setup data binding 
                this.column2DataGridViewComboBox.DataSource = dataSource;
                this.column2DataGridViewComboBox.DisplayMember = "Unit";

                break;

            }
        }



        private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
        {
            ComboBox cb;


            Debug.WriteLine(dataGridView1.CurrentCell.ColumnIndex + "EditControlShowing");
            switch (dataGridView1.CurrentCell.ColumnIndex)
            {
                case 0:
                    
                cb = e.Control as ComboBox;
                if (cb != null)
                {
                    // first remove event handler to keep from attaching multiple:
                    cb.SelectedIndexChanged -= column1DataGridViewComboBox_SelectedIndexChanged;
                    // now attach the event handler
                    cb.SelectedIndexChanged += column1DataGridViewComboBox_SelectedIndexChanged;
                }
                break;
            }
        }

mprice214 wrote:

DataGridViewEditingControlShowingEventArgs does not contain the "column" method.

private void column1DataGridViewComboBox_SelectedIndexChanged(object sender, EventArgs e)
{
    if (dataGridView1.CurrentCell.ColumnIndex != 0)   // <=========== Bombing out construct
    {
        return;
    }

    ComboBox cb = sender as ComboBox;

    int intPrimary = cb.SelectedIndex;
    Debug.WriteLine(intPrimary + "SelectedIndexChanged");

                ................................
                ................................
                ................................
                ................................
         }

private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
    ComboBox cb;


    Debug.WriteLine(dataGridView1.CurrentCell.ColumnIndex + "EditControlShowing");
    switch (dataGridView1.CurrentCell.ColumnIndex)
    {
        case 0:

        cb = e.Control as ComboBox;
        if (cb != null)
        {
            // first remove event handler to keep from attaching multiple:
            cb.SelectedIndexChanged -= column1DataGridViewComboBox_SelectedIndexChanged;
            // now attach the event handler
            cb.SelectedIndexChanged += column1DataGridViewComboBox_SelectedIndexChanged;
        }
        break;
        default:
            // remove event handler to keep it from firing on the wrong column:
            cb.SelectedIndexChanged -= column1DataGridViewComboBox_SelectedIndexChanged;
        break;
    }
}

private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
    ComboBox cb;  // <=============== 1. rename this and move it outside the handler


    Debug.WriteLine(dataGridView1.CurrentCell.ColumnIndex + "EditControlShowing");
    switch (dataGridView1.CurrentCell.ColumnIndex)
    {
        case 0:

        cb = e.Control as ComboBox;  // <============ 2. ensure that <big>all</big> references to cb change to match new name (in this handler only)
        if (cb != null)
        {
            // first remove event handler to keep from attaching multiple:
            cb.SelectedIndexChanged -= column1DataGridViewComboBox_SelectedIndexChanged; // <============== remove this
            // now attach the event handler
            cb.SelectedIndexChanged += column1DataGridViewComboBox_SelectedIndexChanged;
        }
        break;
    }
}

ComboBox hookedCombo;
private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
    Debug.WriteLine(dataGridView1.CurrentCell.ColumnIndex + "EditControlShowing");
    switch (dataGridView1.CurrentCell.ColumnIndex)
    {
        case 0:

        hookedCombo = e.Control as ComboBox;
        if (hookedCombo != null)
        {
            // now attach the event handler
            hookedCombo.SelectedIndexChanged += column1DataGridViewComboBox_SelectedIndexChanged;
        }
        break;
    }
}

private void dataGridView1_EditModeChanged(object sender, EventArgs e)
{
    if (hookedCombo != null)
    {
        hookedCombo.SelectedIndexChanged -= OnCountryComboChanged;
    }
    hookedCombo = null;
}

public partial class Form1 : Form
    {
        DataTable tblPrimary, tblSecondary;
        BindingSource primaryBS, filteredSecondaryBS, unfilteredSecondaryBS;
        
        public Form1()
        {

            tblPrimary = new DataTable("Primary");
            tblPrimary.Columns.Add("ID", typeof(int));
            tblPrimary.Columns.Add("Name", typeof(string));

            tblSecondary = new DataTable("Secondary");
            tblSecondary.Columns.Add("ID", typeof(int));
            tblSecondary.Columns.Add("subID", typeof(int));
            tblSecondary.Columns.Add("Name", typeof(string));

            tblPrimary.Rows.Add(new object[] { 0, "Force" });
            tblPrimary.Rows.Add(new object[] { 1, "Torque" });
            tblPrimary.Rows.Add(new object[] { 2, "Pressure" });

            tblSecondary.Rows.Add(new object[] { 0, 0, "lb" });
            tblSecondary.Rows.Add(new object[] { 1, 0, "N" });
            tblSecondary.Rows.Add(new object[] { 2, 0, "oz" });
            tblSecondary.Rows.Add(new object[] { 3, 1, "in-lb" });
            tblSecondary.Rows.Add(new object[] { 4, 1, "ft-lb" });
            tblSecondary.Rows.Add(new object[] { 5, 1, "N-m" });
            tblSecondary.Rows.Add(new object[] { 6, 2, "PSI" });
            tblSecondary.Rows.Add(new object[] { 7, 2, "Pa" });
            tblSecondary.Rows.Add(new object[] { 8, 2, "bar" });
            
            InitializeComponent();

            primaryBS = new BindingSource();
            primaryBS.DataSource = tblPrimary;
            primaryComboBoxColumn.DataSource = primaryBS;
            primaryComboBoxColumn.DisplayMember = "Name";
            primaryComboBoxColumn.ValueMember = "ID";

            // the ComboBox column is bound to the unfiltered DataView
            unfilteredSecondaryBS = new BindingSource();
            DataView undv = new DataView(tblSecondary);
            unfilteredSecondaryBS.DataSource = undv;
            secondaryComboBoxColumn.DataSource = unfilteredSecondaryBS;
            secondaryComboBoxColumn.DisplayMember = "Name";
            secondaryComboBoxColumn.ValueMember = "ID";

            // this binding source is where I perform my filtered view
            filteredSecondaryBS = new BindingSource();
            DataView dv = new DataView(tblSecondary);
            filteredSecondaryBS.DataSource = dv;
        }
                

       
        private void dataGridView1_CellBeginEdit(object sender, DataGridViewCellCancelEventArgs e)
        {
                if (e.ColumnIndex == secondaryComboBoxColumn.Index)
                {
                    DataGridViewComboBoxCell dgcb = (DataGridViewComboBoxCell)dataGridView1[e.ColumnIndex, e.RowIndex];
                    dgcb.DataSource = filteredSecondaryBS;

                    this.filteredSecondaryBS.Filter = "subid = " +
                        this.dataGridView1[e.ColumnIndex - 1, e.RowIndex].Value.ToString();
                }
            
         }

        private void dataGridView1_CellEndEdit(object sender, DataGridViewCellEventArgs e)
        {
           
                if (e.ColumnIndex == this.secondaryComboBoxColumn.Index)
                {
                    DataGridViewComboBoxCell dgcb = (DataGridViewComboBoxCell)dataGridView1[e.ColumnIndex, e.RowIndex];
                    dgcb.DataSource = unfilteredSecondaryBS;

                    this.filteredSecondaryBS.RemoveFilter();
                }
        
        }

William Winner wrote:

That didn't tell you anything? You couldn't tell right away that you weren't getting what you expected and that that was the problem?