How can I clear rows in DataGridView with C#?

Question

Following Error in this line.

datagridview1.Rows.Clear()

but this line gives error:

Cannot clear this list.

Answer 1

Simply add this line at beginning of your event:

dgv_nameOfGridView.DataSource=false;

Now every time you click it will erase the dgv..

Answer 2

I also had similiar problem when I try to clear DataSource of a DataGridView after I had binded it to a DataTable with:

DataTable DT = ... ; // fill it
datagridview1.DataSource = DT;

when I try to clear it's rows later with the following code:

datagridview1.DataSource = null

I get this error:

ERROR: Object reference not set to an instance of an object

This object reference ERROR problem already solved in here. But I managed to solve my own problem (clearing DataGridView rows) with this code:

DataTable DT = (DataTable)datagridview1.DataSource;
if (DT != null) 
    DT.Clear();

I know that this question was asked a very long time ago, but I hope my solution would solve someone problems.

Answer 3

You have to Clear datasource not datagridview rows.

datagridview1.DataSource = null;

Another way is

1) Dont assign direct datasource to gridview. add rows from datatable to gridview

      foreach (DataRow row in dataTable.Rows)
        {
            var dataGridRow = new DataGridViewRow();
            dataGridRow.CreateCells(datagridview1);

            for (int i = 0; i < row.ItemArray.Length; i++)
            {
                dataGridRow.Cells[i].Value = row.ItemArray[i];
            }

            datagridview1.Rows.Add(dataGridRow);
        }

then use

datagridview1.Rows.Clear()

Answer 4

Since you are using a bound grid, have you tried to call your loading function twice and verified that the data is not doubling?

Since it is bound, loading twice ought to not duplicate the data.

http://www.vbforums.com/showpost.php?s=aa5f116586c00a2d9ea15e3727fc5c2f&p=2841192&postcount=9

Answer 5

Is your DataGridView bound to a DataSource, i think thats why its not allowing you to clear it since its bound to an underlying DataTable or List.

you could try setting the DataSource Property to null

datagridview1.DataSource = null; for clearing

Answer 6

If you load your DataGridView with a parameter, you can send an empty parameter to it. This will clear your DataGridView without having to set its DataSet to null.

For example, I load my DataGridView with a Code, when I fill a TextBox.

this.dataTable1TableAdapter.Fill(this.ds_MyDataSet.DataTable1, TextBox1.Text);

If I want to clear its content, then

this.dataTable1TableAdapter.Fill(this.ds_MyDataSet.DataTable1, "");