i'm trying to hide the first column ("id") of a lookupedit after I load the coresponding dataset.

           lCapitol.Properties.DataSource = nContabDataSet.Tables["capitol"];
           lCapitol.Properties.Columns[0].Visible = false;       //also tried            lCapitol.Properties.Columns["id"].Visible = false;
           lCapitol.Properties.DisplayMember = "Cod";
           lCapitol.Properties.ValueMember = "id";
           

 at the second line i get the following error:

Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index 

OR     Object reference not set to an instance of an object.  when when using ["id"].

 

Hello,

Gigi gigi:

i get the following error:

Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index 

OR     Object reference not set to an instance of an object.  when when using ["id"].

As long as you are not explicitly populating the LookupEdit's Columns collection there will be no columns available - the LookupEdit's auto populating mechanism doesn't add columns to the Columns collection, thus you are running into an exception when accessing the collection. 

Instead of hiding the "id" column I would like to suggest to add all the other columns to the Columns collection:

    this.lookupEdit1.Properties.Columns.Add(new LookUpColumnInfo("Cod", 50, "Cod"));
    this.lookupEdit1.Properties.Columns.Add(new LookUpColumnInfo(...);

Hope this helps,
Holger

I had the same problem and your solution helps a great deal, thankyou!