merging two datagridview columns into one new column

Question

i want to merge two datagridview columns into one new column.

i first change Visible property of two col to false, then i try to add new col which that value must be

Answer 1

Try this (it works for me):

reportResultForm.dgvResult.Columns.Add("newColumn", "New Column");
        foreach (DataGridViewRow row in reportResultForm.dgvResult.Rows)
        {
            string height= row.Cells["Height"].Value.ToString();
            string width= row.Cells["Width"].Value.ToString();
            string formattedCol= string.Format("{0} per {1}", height, width);
            row.Cells["newColumn"].Value = formattedCol;
        }

Answer 2

You can made your own implementation of the DataGridViewTextBoxCell and override GetFormattedValue method for it. There you can return the formatted value for your column below is an example:

// use custom DataGridViewTextBoxCell as columns's template
col.CellTemplate = new MyDataGridViewTextBoxCell();

...

// custom DataGridViewTextBoxCell implementation 
public class MyDataGridViewTextBoxCell : DataGridViewTextBoxCell
{
    protected override Object GetFormattedValue(Object value,
        int rowIndex,
        ref DataGridViewCellStyle cellStyle,
        TypeConverter valueTypeConverter,
        TypeConverter formattedValueTypeConverter,
        DataGridViewDataErrorContexts context)
    {
        return String.Format("{0} per {1}",
            this.DataGridView.Rows[rowIndex].Cells[0].Value,
            this.DataGridView.Rows[rowIndex].Cells[1].Value);
    }
}

hope this helps, regards