Fill color text in girdview ?

So how I fix ? I use this method only 2

[code]
[/code]

For more on dataGridView1 format: date type, numeric type, string type when compared to error "Object reference not set to an instance of an object."
[code]
private void txtSearchby_TextChanged(object sender, EventArgs e)
        {
            DataView dv = new DataView(dt); // dataTable 
            String filter = String.Format(Name LIKE '%{0}%' Or HomePhone LIKE '%{0}%' ,...., txtSearchby.Text);
            dv.RowFilter = filter;            
            dataGridView1.DataSource = dv;


            // Fill Highttext Color ?
            foreach (DataGridViewRow row in dataGridView1.Rows)
            {
                string RowType = row.Cells[0].Value.ToString(); // Error here: Object reference not set to an instance of an object.
                if (RowType == txtSearchby.Text)
                {
                    row.DefaultCellStyle.BackColor = Color.Yellow;
                    row.DefaultCellStyle.ForeColor = Color.White;
                }
            }
        }
[/code]

I am not sure, may be help this code.
foreach (DataGridViewRow row in mydataGridView.Rows)
{ string RowType = row.Cells[0].Value.ToString();
  if (RowType == "Type A")
{ row.DefaultCellStyle.BackColor = Color.Red; row.DefaultCellStyle.ForeColor = Color.White; }
 else if (RowType == "Type B")
{ row.DefaultCellStyle.BackColor = Color.Yellow; row.DefaultCellStyle.ForeColor = Color.Black;
 }
 }

I'm looking for code support on winform, I using for DataGridViewRow

another solution may be
take label in your column and bind amount on that label and on row databound event
find control of that label and change label color dynamically based on condition

debug your code and check your conditions and check which column do you want to colored

your image is not opening in  your link

your image is not clear but
as i understadnd you want to change row color
then
on gridview Rowdatabound event

  if (e.Row.RowType == DataControlRowType.DataRow)   {
  if (convert.ToInt32(e.Row.Cells[2].Text)>1)
  {
 
  e.Row.Cells[2].ForeColor = System.Drawing.Color.Yellow;
  }
  }