CODEWITHSUNDEEP
c#asp.net.netwinformscombobox
Sean BUTCHER
Sean BUTCHER

Reputation: 13

How to see if a value is in a combo box

In my winform I need to check if a string value inputted by the user is within a combo box, where the values of the combo box's data is sourced from a database.

Is it possible to simply check if the user's value is already in the combo box or will I have to manually check the database to see if the data is present? 

    private void Button1_Click(object sender, EventArgs e)
    {
        if (!questionList.Items.Contains(customQ.Text.Trim()))
        {
            dbconnect.addQ(customQ.Text);
            refreshBox();
        }
    }

I have tried using contain but it always returns false, even if the data isn't in the combo box, any feedback is appreciated :)

Upvotes: 0

Views: 1099

Answers (2)

Vyron Paschalidis
Vyron Paschalidis

Reputation: 231

Casting the Items as strings will work for what you want. Items are handled as an ObjectCollection and their IEnumerable wont even try checking if a string is contained.

private void Button1_Click(object sender, EventArgs e)
{
    if (!questionList.Items.Cast<string>().Contains(customQ.Text.Trim()))
    {
        dbconnect.addQ(customQ.Text);
        refreshBox();
    }
}

The code above worked as it should in my testing and hopefully it will work for you.

Upvotes: 0

Josh Greenberg
Josh Greenberg

Reputation: 323

You should be able to use the FindStringExact method to determine if a item already exists in the ComboBox.

if (questionList.FindStringExact(customQ.Text.Trim()) < 0)
{
    // The item was not found to already exist
}

You can read more about the FindStringExact method within the .NET documentation:

https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.combobox.findstringexact?view=netframework-4.7.2

Hope this helps.

Upvotes: 1

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