CODEWITHSUNDEEP
c#winformscombobox
smokeAndMirrors
smokeAndMirrors

Reputation: 155

Make ComboBox options non-selected based on previous comboboxes

Sorry if the question is confusing, this is what I wish to do.

I have 4 comboboxes in a winform. All 4 comboboxes have the same information in them (ie Street Addresses)

If in the first combobox I select, for instance, First St - how do I make First St greyed out (or unselectable) in the other comboboxes.

EDIT:

I have the following code which i place in comboBox1_SelectedIndexChanged:

    for (int i = 0; i < comboBox2.Items.Count; i++)
    {
        if (comboBox2.Items[i] == comboBox1.SelectedItem)
        {
            comboBox2.Items.Remove(comboBox2.Items[i]);

                i--;
            }
        }
    }

This works fine for removing the first choice from subsequent comboboxes, however if I accidentally choose the wrong street and then select the correct street from the first comboBox, both streets are removed from the second comboBox

e.g. -> 1st selection Main St oops I mean First St

now I go to the second comboBox and both Main St and First St have been removed. Is the a way around this, or do I have to hope the user will not make a mistake?

Upvotes: 0

Views: 170

Answers (2)

Fabio
Fabio

Reputation: 32445

Or use approach from another side.
Just check if selected value from second ComboBox is already selected in another ComboBox controls

string _notSelected = "n/a";
var streets = new[] {_notSelected, "Street One", "Street Two"};
this.comboBox1.DataSource = streets;
this.comboBox2.DataSource = streets;

void comboBox2_SelectedIndexChanged(object sender, EventArgs e)
{
    ComboBox current = (ComboBox)sender;
    if(current.SelectedValue != null)
    {
        //Here you can compare indexes of all comboboxes or values
        if(this.combobox1.SelectedValue != null && 
           this.combobox1.SelectedValue.ToString().Equals(current.SelectedValue.ToString())
        {
            current.SelectedValue = _notSelected;
        }

        // ...same for other comboboxes...
    }
}

Upvotes: 0

Mikko Viitala
Mikko Viitala

Reputation: 8394

For example, if you have comboBox1 and comboBox2, then you could filter the available options based on previous control's selection. 

var data = new[] {"a", "b", "c"};

comboBox1.DataSource = comboBox2.DataSource = data;

comboBox1.SelectedValueChanged += (sender, args) =>
    comboBox2.DataSource = data.Where(item => 
        !item.Equals(comboBox1.SelectedValue)).ToArray();

Upvotes: 0

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