DataGridView, Sorting and Paging - using DataView
I needed ability to sort as well as pagination in a data grid view for an application. There are many approaches of implementing it but we had data in memory, prefetched. I used a dataview to create sorted, then paged based on counters generated manually. Here is the code for the same, but somehow I am not satisfied with the approach as its slow on large data sets. Any ideas how to do it faster?
//Form Load add a column, which is used keeping the sorted order, and then paging.
//Add an event handler to the DatagridView Sorted event
private void PageDemoForm_Load(object sender, EventArgs e)
{
productsDataTable.Columns.Add(
"RecordIndex", typeof(int));
pageNumberTextBox.Text = currentPage.ToString();
dataGridViewControl.Sorted +=
new EventHandler(dataControl_Sorted);
SetView(currentPage);
}
//Datagridview Sorted Event handler
private void dataControl_Sorted(object sender, EventArgs e)
{
SetView(currentPage);
}
//Sort the View, refresh record indexes, then filter the view on the indexes which fall between lowbound & highBound
//here pageSize is a class level constant which can be configured as needed.
private void SetView(int pageNumber)
{
int lowBound = pageSize * (pageNumber - 1);
int highBound = pageSize * pageNumber;
string sortExpression = (dataGridViewControl.SortedColumn == null) ? string.Empty : dataGridViewControl.SortedColumn.DataPropertyName + " " + ((dataGridViewControl.SortOrder == System.Windows.Forms.SortOrder.Ascending) ? "ASC" : "DESC");
//Created a sorted view
DataView pagedView = new DataView(productsDataTable, string.Empty, sortExpression, DataViewRowState.CurrentRows);
//generate row indexes, this is a hidden column in grid.
for (int i = 0; i < pagedView.Count; i++)
{
pagedView[i][
"RecordIndex"] = i + 1;
}
//set RowFilter to get desired page records.
pagedView.RowFilter =
"RecordIndex > " + lowBound + " AND " + highBound + " >= RecordIndex";
//hid the RecordIndex column from grid
DataGridViewTextBoxColumn invisibleColumn = new DataGridViewTextBoxColumn();
invisibleColumn.Visible =
false;
invisibleColumn.DataPropertyName =
"RecordIndex";
this.dataGridViewControl.Columns.Add(invisibleColumn);
this.dataGridViewControl.DataSource = pagedView;
}
//Click event for next page button
private void NextPage(object sender, EventArgs e)
{
currentPage =
int.Parse(pageNumberTextBox.Text) + 1;
pageNumberTextBox.Text = currentPage.ToString();
SetView(currentPage);
}
//Click event for previous page button
private void PreviousPage(object sender, EventArgs e)
{
currentPage =
int.Parse(pageNumberTextBox.Text) - 1;
pageNumberTextBox.Text = currentPage.ToString();
SetView(currentPage);
}
//Click event for last page button
private void LastPage(object sender, EventArgs e)
{
currentPage =
this.productsDataTable.Rows.Count / pageSize;
int residue = this.productsDataTable.Rows.Count % pageSize;
if (residue > 0)
{
currentPage++;
}
pageNumberTextBox.Text = currentPage.ToString();
SetView(currentPage);
}
//Click event for first page button
private void FirstPage(object sender, EventArgs e)
{
currentPage = 1;
pageNumberTextBox.Text = currentPage.ToString();
SetView(currentPage);
}