How do I change column types in datagridview at runtime

See more:

C#

DataGridView

Hello everyone,


I want to merge some of the rows in my datagridview and I'm using this article.



When I load my datagridview, I want to change the type of my columns so that they can have the "rowspan" and "colspan".


How can I do it?

What I have tried:

Here's how I load my datagridview :

dataGridView1.DataSource = null;
                dataGridView1.Rows.Clear();
                SqlConnection cn = new SqlConnection();
                SqlCommand cmd = new SqlCommand();
                cn.ConnectionString = @"CONNECTION STRING"; 
                cmd.Connection = cn;
                cmd.Connection.Open();
                cmd.CommandText = $"SELECT * FROM Table where column3!= '' "; 
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                DataTable dt = new DataTable();

                
                
              
                da.Fill(dt);


                BindingSource source = new BindingSource();
                source.DataSource = dt;
                dataGridView1.DataSource = dt;