allow only distinct values in ComboBox

Question

In my project, I'm trying to populate ComboBox from DataSet. I succeeded in populating but the values inside the ComboBox are not distinct (Because it shows the values present in DataSet). I cant bind the ComboBox to DataSet because I'm adding "Select" text at first of populating the values.

ComboBox --> cmb
DataSet --> ds
DataSet Column Name --> value(string)

---

Here is my code:

cmb.Items.Clear();
cmb.Items.Add("Select");
for (int intCount = 0; intCount < ds.Tables[0].Rows.Count; intCount++)
{
    cmb.Items.Add(ds.Tables[0].Rows[intCount][value].ToString());
}
cmb.SelectedIndex = 0;

How would I allow distinct values (or restrict duplicate values) inside the ComboBox?

Answer 1

for (int intCount = 0; intCount < ds.Tables[0].Rows.Count; intCount++)
{
     var val=ds.Tables[0].Rows[intCount][value].ToString();

     //check if it already exists
     if(!cmb.Items.Contains(val))
     {
            cmb.Items.Add(val);
     }
}

Answer 2

You can try:

cmb.Items.Clear();
cmb.Items.Add("Select");
cmb.Items.AddRange(dds.Tables[0].AsEnumerable()
                           .Select(x=>x[value].ToString())
                           .Distinct());

• It uses linq to select the values, applying Distinct() selects unique values
• You can apply an OrderBy if you want the values to be sorted.

Answer 3

for(int i = 0; i < cmb.Items.Count; i++)
{
    for(int y = 0; y < cmb.Items.Count; y++)
    {
         if( y != i && cmb.Items[i].Text == cmb.Items[y].Text)
         {
              cmb.Items.RemoveAt(i);
              break;
         }
    }
}