Dynamic Combo Box problem

Question

I am having a problem with a combo box. I have three radio buttons that control the comboxes. Only one is visible. I have 4 combo boxes. The combo boxes are populated with data from a Access Database.When a user selects a item from the first combo box it then calls a stored procedure and turns the second combo box visible and so forth until the last combo box. The way I have it set right now is I have a method that gets the string from the selection in the first combo box then turns the second combobox visible and then calls another method which the repeats the first method. Problem is that the combobox does not appear until select a different radio button. When I select the first radio button again after deselcting it, it then appaears. How do I do it so that the comboboxes will dyamically appear right after each other based on the selection in the combobox? Here is a relevant code from my project.

private void GetProducColors()
{
     //Misc DB calls to stored procedure Not needed to look at
    //Populates the first combobox

    //Gets the string selection
    string strSelection = cmbProductColor.SelectedItem.ToString();
    //Turns first combobox visible
     this.cmbFirstColor.Visible = true;
     //Send String to First Imprint Color
     GetFirstImprintColors(strSelection);
}

private void GetFirstImprintColors(string strSelection)
{

}

Johnny · Answer

Bangs head on wall. Yup that worked. I am getting something else that is causing the program to crash but it is working now. Thanks for the help

Michael · Answer

John I am not sure I am clear on your real intent but... The event I used is the comboBox SelectedValueChanged. I took the code you had in your previous post and used this event to call the GetFirstBox function and make the second comboBox visible. In this way when the otpButtonOne is checked comboBoxOne is set up with a list of colors. comboTwo and Three are not visible. When the user selects a color the cmbComboOne_SelectedValueChanged event is called gets the selection text and calls GetFirstBox that sets up comboBoxTwo and makes it visible. At this point I am not sure how you want things to work but hopefully this helps. Here's the code. public Form1() { InitializeComponent(); } private string m_selection; private void optButtonOne_CheckedChanged( object sender EventArgs e) { this .cmbComboOne.Items.Clear(); this .cmbComboTwo.Visible = false ; this .cmbComboThree.Visible = false ; this .cmbComboOne.Text = Select a Color ; this .cmbComboOne.Items.AddRange( new object [] { blue  green  purple }); //m_selection = this.cmbComboOne.SelectedItem.ToString(); //GetFirstBox(m_selection); } private void optButtonTwo_CheckedChanged( object sender EventArgs e) { if (optButtonTwo.Checked == true ) { this .cmbComboOne.Items.Clear(); this .cmbComboOne.Text = Select a Item ; this .cmbComboTwo.Visible = false ; this .cmbComboThree.Visible = false ; this .cmbComboOne.Items.AddRange( new object [] { cars  boats  trains }); } } public void GetFirstBox( string selection) { this .cmbComboTwo.Visible = true ; this .cmbComboTwo.Items.Clear(); this .cmbComboTwo.Text = Select a Second Item ; this .cmbComboTwo.Items.AddRange( new object [] { yellow  red  orange }); } private void cmbComboOne_SelectedValueChanged( object sender EventArgs e) { m_selection = this .cmbComboOne.SelectedItem.ToString(); GetFirstBox(m_selection); } }

Johnny · Answer

Hi Micheal what event handler did you use to get your second combobox to become visible. created a generic Form with just combo boxes to test this but I cannot get my second combobox to become visible. Here is my generic form. namespace Combo_Test { public partial class Form1 : Form { private string m_selection; public Form1() { InitializeComponent(); } private void optButtonOne_CheckedChanged(object sender EventArgs e) { this.cmbComboOne.Items.Clear(); this.cmbComboTwo.Visible = false; this.cmbComboThree.Visible = false; this.cmbComboOne.Text = Select a Color; this.cmbComboOne.Items.AddRange(new object[] { blue  green purple }); m_selection = this.cmbComboOne.SelectedItem.ToString(); GetFirstBox(m_selection); } private void optButtonTwo_CheckedChanged(object sender EventArgs e) { if (optButtonTwo.Checked == true) { this.cmbComboOne.Items.Clear(); this.cmbComboOne.Text = Select a Item; this.cmbComboTwo.Visible = false; this.cmbComboThree.Visible = false; this.cmbComboOne.Items.AddRange(new object[] { cars boats trains }); } } public void GetFirstBox(string selection) { this.cmbComboTwo.Visible = true; this.cmbComboTwo.Items.Clear(); this.cmbComboTwo.Text = Select a Second Item; this.cmbComboTwo.Items.AddRange(new object[] { yellow red orange }); } } }

Johnny · Answer

I am really not sure why my code is not working. I am going to try and test it without the DB call and see if it works. It is odd how it only works when you switch to another radio button and then switch back. What event handler would you use for the second question?

Michael · Answer

Sorry that did not work for you may be I do not understand the problem. I do not see it in some test code I tried. I copied your code snipit into a form with three CBs only one visible. I put some bogus data in that CB. I then connected the visible CB to an event handler for event SelectedValueChanged. In the event handler I called your GetProducColors(). The second CB became visible. But of course I do not have the database connection etc. An event handler could be used to do the something that you want from your second question.

Johnny · Answer

That didn't work. But after doing some testign on a generic model the only way Iw as able to do this was to use a if statement based on the combobox data. But since the combobox data is not know before hand I cannot do this on this form. is there a way to do somethijng along these lines? if anything is selected from the combobox do something?

Michael · Answer

Try forcing the form to redraw with the form class method Refresh() after making the CB visible.