Using a string array to get information from a list of multiboxes

Question

So I have an array that has the first portion of comboboxes on an order form. the comboboxes hold data (x1, x2, x3, x4), and are named ketchupCount, mustardCount, etc...

What I am trying to do is use the array normalCondoments array + Count to generate the correct combobox name to set the SelectedIndex value to -1 which is unselected. Eventually It will get the value, not set it, and print it to a string...

The expected code should read ketchupCount.SelectedIndex

    string[] normalCondoments = { "ketchup", "mustard", "mayo", "ga",
                                  "lettuce", "tomato", "pickles", "onion" };
    foreach (var nCondoment in normalCondoments)
                {
                    string str = nCondoment + "Count";
                    MessageBox.Show("letter:" + nCondoment);
                    str.SelectedIndex = -1;
                }

The error I am getting is:

"String does not contain a selected definition for 'SelectedIndex' and no accessable extension for 'SelectedIndex' accepting a first argument of type 'string' ncould be found."

VS doesnt give a fix for this, I have looked and looked, but havent found something similar to this error. Thanks in advance

What is a multibox? Are you refering to a ComboBox? A ListBox? Can you specify the platform you're using? Are you trying to use an object's reference with a string set to its name? — Jimi, Apr 30 '19 at 04:04
I apologize it is the combo box, editing above to reflect correct terminology — Michael Kardee, Apr 30 '19 at 16:12

score 0 · Answer 1 · answered Apr 30 '19 at 04:05

This is not javascript, you must use the variable not a its name

ketchupCount.SelectedIndex = -1;
mustardCount.SelectedIndex = -1;
mayoCount.SelectedIndex = -1;
gaCount.SelectedIndex = -1;
lettuceCount.SelectedIndex = -1;
tomatoCount.SelectedIndex = -1;
picklesCount.SelectedIndex = -1;
onionCount.SelectedIndex = -1;

Or create an array to hold them

var normalCondoments = new multibox[] {ketchupCount, mustardCount, mayoCount, gaCount,
     lettuceCount, tomatoCount, picklesCount, onionCount};
foreach(var nCondoment in normalCondoments)
  nCondoment.SelectedIndex = -1;

I dont need an array to hold them, I just need to display them. The issue is that, I cant use a variable string to loop through all 8, I tried calling string[] normalCondoments = {ketchupCount, mustardCount, blah} It is still reading as a string. — Michael Kardee, Apr 30 '19 at 16:17

score 0 · Accepted Answer · answered Apr 30 '19 at 16:40

You can get a reference of a Control using the Container.Controls[] collection.
This collection can be indexed by a Int32 value or a String, representing a Control's name.

In your case, if the ComboBoxes are all direct children of the Form, your code could be:

string[] normalCondoments = { "ketchup", "mustard", "mayo", "ga",
                              "lettuce", "tomato", "pickles", "onion" };

foreach (var nCondoment in normalCondoments) {
    (this.Controls[$"{nCondoment}Count"] as ComboBox).SelectedIndex = -1;
}

Otherwise, replace this with the actual container.

If instead these controls are children of different containers, you need to find them.
In this case, use the Controls collection's Find() method, specifying to searchAllChildren:

foreach (var nCondoment in normalCondoments) {
    var cbo = (this.Controls.Find($"{nCondoment}Count", true).FirstOrDefault() as ComboBox);
    if (cbo != null) cbo.SelectedIndex = -1;
}

You Jimi are a genius, this has been driving me crazy for several days, I will post the working code in al ittle bit — Michael Kardee, Apr 30 '19 at 19:38
I did have to add the container name instead of "this" `code`int answer; foreach (var nCondoment in normalCondoments) { answer = (nCondomentsContainer.Controls[$"{nCondoment}Count"] as ComboBox).SelectedIndex; string str = nCondoment + "Count"; if (answer > -1) { MessageBox.Show(nCondoment +" " + (answer+1)); rCondoments = rCondoments + nCondoment + " " + (answer + 1) + "\n"; } } — Michael Kardee, Apr 30 '19 at 19:43

Using a string array to get information from a list of multiboxes

2 Answers2