Sorting and Paging of an Generic GridView

Introduction

This might be usefull if you would like to use hardcoded column names ... Most of the code is sourced from here: strong coders and here , so I quess I can't call my self author of this article, but more like wrapper producer ; )

Background

Separate presentation logic from data layer .... We asume here you have already your dataset, so I am not going to show .. how to populate it with values ... (for this one later one another article ; ) Using the code Just copy paste the code and play with it ... Here is the gridview in the aspx file

"table_list_gv" runat="server"
ToolTip="The list of projects matching your criteria" AccessKey="E"

CellPadding="4" BorderColor="#3366CC" Font-Size="Smaller"
HorizontalAlign="Left" BorderStyle="None" BorderWidth="1px" BackColor="White"
EnableViewState="true" EnableTheming="False"

AutoGenerateColumns="true"
PageIndex="0"
ActivePageIndex="0"
EmptyDataText="No records found"
PagerSettings-Mode="NumericFirstLast"
PageSize="3"
OnRowCreated="OnRowCreated"
AllowPaging="true" AllowSorting="true"
OnPageIndexChanging="Table_list_gv_PageIndexChanging"
OnSorting="Table_list_gv_Sorting"
OnRowDataBound="Table_list_gv_RowDataBound">

"#99CCCC" ForeColor="#003399">
"#003399" HorizontalAlign="Left" BackColor="#99CCCC">
"True" BackColor="#003399" BorderColor="#000066" BorderStyle="Solid" BorderWidth="1px"
Height="14px" HorizontalAlign="Center" VerticalAlign="Top" ForeColor="#CCCCFF" >

No reports were found with the supplied criteria

This is the method for creating the gridview Note: I do not create them in the page.aspx.cs files but throw the references ... so the following code should be called like this GUI.GUIHelper.PrepareSimpleGV ( ref msg , ref table_list_gv , ref rds ); (where GUI. is the name of the namespace I have those utilities ; ), the GUIHelper is the name of the Class containing the method and PrepareSimpleGV is the method - well you may be should have skipped this ; )

Here is a sample datapopulator method , just for the sake of the example:

						DataSet rds = new DataSet ();
						DataTable dt = new DataTable("myDynamicTable");
						// Create a DataColumn instances

						DataColumn dValue = new DataColumn();
						DataColumn dMember = new DataColumn();

						dValue.ColumnName = "Id";
						dValue.DataType = Type.GetType("System.Int32");
						
						dMember.ColumnName = "Name";
						dMember.DataType = Type.GetType("System.String");

						// Add these DataColumns into the DataTable
						dt.Columns.Add(dValue);
						dt.Columns.Add(dMember);



						for ( int i = 0 ; i<100 ; i++) 

						{

										DataRow dr = dt.NewRow();
										dr["Id"] = i;
										dr["Name"] = "Name " + System.Convert.ToString ( i ) ;

						// Add the row into the table

						dt.Rows.Add(dr);
						}
						rds.Tables.Add ( dt );
						
//store the dataset in a session variable to be able to use it when assigning the datasource
Session [ "pageName.rds" ] = rds;
} //eof method

public static void PrepareSimpleGV ( ref string msg , ref System.Web.UI.WebControls.GridView table_list_gv ,
ref System.Data.DataSet rds)
{
if (rds == null)
{ //just add an empty one in order to present the EmptyDataTemplate
rds = new DataSet ();
DataTable dt = new DataTable ();
rds.Tables.Add ( dt );
}
table_list_gv.DataSource = rds.Tables [ 0 ];
//debug Utils.Debugger.DebugDataSet ( "just after table_list_gv.DataSource = rds.Tables [ 0 ];" , ref rds );
table_list_gv.AllowPaging = true;
table_list_gv.AllowSorting = true;
table_list_gv.PageIndex = 0;
table_list_gv.EnableSortingAndPagingCallbacks = false;
table_list_gv.Visible = true;
table_list_gv.DataBind ();
return;

} //eof private static void PrepareSimpleGV(ref System.Web.UI.WebControls.GridView table_list_gv )

Now put the following Properties in your page.aspx.cs file :

 #region Properties

//===========================SORTING PROPERTIES START
private string GridViewSortDirection
{
get { return ViewState [ "SortDirection" ] as string ?? "ASC"; }
set { ViewState [ "SortDirection" ] = value; }
}

private string GridViewSortExpression
{
get { return ViewState [ "SortExpression" ] as string ?? string.Empty; }
set { ViewState [ "SortExpression" ] = value; }
}

private string GetSortDirection ()
{
switch (GridViewSortDirection)
{
case "ASC":
GridViewSortDirection = "DESC";
break;

case "DESC":
GridViewSortDirection = "ASC";
break;
}

return GridViewSortDirection;
}



//===========================SORTING PROPERTIES END

#endregion //Sorging and Paging Properties

The handlers for implementing the paging and sorting Now put those in the Methods region of your page.aspx.cs class:

//======================================== GRIDVIEW EventHandlers START
#region GridViewEventHandlers
protected void OnRowCreated ( object sender , GridViewRowEventArgs e )
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
e.Row.Cells [ 0 ].CssClass = "hiddencol";
}
else if (e.Row.RowType == DataControlRowType.Header)
{
e.Row.Cells [ 0 ].CssClass = "hiddencol";
}
} //eof protected void OnRowCreated ( object sender, GridViewRowEventArgs e )


protected void RowDataBound_Handler ( Object table_list_gv , GridViewRowEventArgs e )
{

} //eof method

protected void Table_list_gv_RowDataBound ( object sender , GridViewRowEventArgs e )
{

// apply custom formatting to data cells
if (e.Row.RowType == DataControlRowType.DataRow)
{
TableCell cell;
// set formatting for the category cell
cell = e.Row.Cells [ 0 ];
cell.Width = new Unit ( "120px" );
cell.Style [ "border-right" ] = "3px solid #666666";
cell.BackColor = System.Drawing.Color.LightGray;

// set formatting for value cells
for (int i = 1; i < e.Row.Cells.Count; i++)
{
cell = e.Row.Cells [ i ];

// right-align each of the column cells after the first
// and set the width
cell.HorizontalAlign = HorizontalAlign.Right;
cell.Width = new Unit ( "90px" );

// alternate background colors
if (i % 2 == 1)
cell.BackColor
= System.Drawing.ColorTranslator.FromHtml ( "#EFEFEF" );

} //eof set formatting for value cells

} //eof if this is row


// apply custom formatting to the header cells
if (e.Row.RowType == DataControlRowType.Header)
{
foreach (TableCell cell in e.Row.Cells)
{
cell.Style [ "border-bottom" ] = "3px solid #666666";
cell.BackColor = System.Drawing.Color.LightGray;
cell.ForeColor = System.Drawing.Color.Blue;
}
} //if (e.Row.RowType == DataControlRowType.Header)



} //eof protected void table_list_gv_RowDataBound ( object sender, GridViewRowEventArgs e )



protected void Table_list_gv_PageIndexChanging ( object sender , GridViewPageEventArgs e )
{
Session [ "reports.aspx.cs.SelectedIndexChanged" ] = 1;

table_list_gv.DataSource = SortDataTable ( table_list_gv.DataSource as DataTable , true );
table_list_gv.PageIndex = e.NewPageIndex;
table_list_gv.DataBind ();
//Session["ClickSearch"] = true;

} //EOF Table_list_gv_PageIndexChanging(object sender, GridViewPageEventArgs e)



protected DataView SortDataTable ( DataTable dataTable , bool isPageIndexChanging )
{

if (dataTable != null)
{
DataView dataView = new DataView ( dataTable );
if (GridViewSortExpression != string.Empty)
{
if (isPageIndexChanging)
{
dataView.Sort = string.Format ( "{0} {1}" , GridViewSortExpression , GridViewSortDirection );
}
else
{
dataView.Sort = string.Format ( "{0} {1}" , GridViewSortExpression , GetSortDirection () );
}
}
return dataView;
}
else
{
return new DataView ();
}
} //eof SortDataTable


protected void Table_list_gv_Sorting ( object sender , GridViewSortEventArgs e )
{
Session [ "reports.aspx.cs.SelectedIndexChanged" ] = 1;

GridViewSortExpression = e.SortExpression;
int pageIndex = table_list_gv.PageIndex;
table_list_gv.DataSource = SortDataTable ( table_list_gv.DataSource as DataTable , false );
table_list_gv.DataBind ();
table_list_gv.PageIndex = pageIndex;
} //eof table_list_gvSorting

#endregion //GridViewEventHandlers
//======================================== GRIDVIEW EventHandlers END

Points of Interest

Note, that the ViewState in the page should be enabled ... Note , that if you are getting the dataset from a stored procedure is always better to use select columnName as 'Nice Column Name for End User Reading ' .. Note , that I create the dynamic controls always earlier than in the page_load (for this one later another article ; ) Questions: Well how to disable programatically paging during run time ? and put it into the footer , or add another drop down for selecting the number of rows to display on a page ...