从数据网格视图中选择一部分数据C＃

Question

I am trying to select a portion of data from a datagridview with a mouse drag which is getting information from a text file, and then update the datagridview with this selected data.

UPDATE:

Initial error of being unable to clear the grid view is resolved, now when the selected data is trying to be re-entered into the grid this line of text appears in the datagrid where the data should be: "DataGridViewRow { Index=-1 }"

   private void btnUpdate_Click(object sender, EventArgs e)
    {
        List<DataGridViewRow> rowCollection = new List<DataGridViewRow>();
        foreach (DataGridViewRow row in dataGridView1.SelectedRows)
        {
            rowCollection.Add(dataGridView1.Rows[row.Index]);
        }

           dataset.Tables[0].Clear();

        foreach (DataGridViewRow row in rowCollection)
        {
           // dataGridView1.Rows.Add(row);
            dataset.Tables[tableName].Rows.Add(row);

        }
    }

Here is the initial code for displaying the information in the datagridview:

foreach (string row in rows)
            {
                //Adds time to the array
                var items = new List<string> { timeS };
                items.AddRange(row.Split(delimeter.ToArray()));

                speed = Convert.ToDouble(items[2]);
                //converts 'speed' to a double and divides by 10 to display the correct value
                speed = speed / 10;
                items[2] = speed.ToString();
                dataset.Tables[tableName].Rows.Add(items.ToArray());
                //Adds the interval time to Dtime for each row
                Dtime = Dtime.AddSeconds(inter);

            }
            //selects where to display the data
            this.dataGridView1.DataSource = dataset.Tables[0].DefaultView;
        }

Any help would be appreciated!

Cheers.

Answer 1

You can not clear the DataGridView.Rows, because you have specified a datasource. You must clear the DataSource of the DataGridView.

Instead of

dataGridView1.Rows.Clear();

write :

dataset.Tables[0].Clear();

EDIT: You have a mistake in your Code ... You can't add a DataGridViewRow in a Table This code fixes your issue:

    foreach (DataGridViewRow row in rowCollection)
    {
        DataRow r =  dataset.Tables[tableName].NewRow();
        //
        //write the data in the DataRow and then add the datarow in your           datatable
        dataset.Tables[tableName].Rows.Add(r);

    }