One major downsides of using a checkbox in a GridView control to handle mass updates and deletes is that the state of the checkboxs will be lost when going to another page.
To work around this were going to have to write some code to save and load the state of the checkboxes.
You can download the files below.
The 1st thing we want to do is set up our GridView and a DataSource.
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Grid View Check Box Example</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:GridView ID="Gridview1" OnDataBound="Gridview1_OnDataBound" runat="server" Width="100%" OnPageIndexChanging="Gridview1_PageIndexChanging" AllowPaging="True" AutoGenerateColumns="False" DataKeyNames="recordID" DataSourceID="AccessDataSource1">
<Columns>
<asp:BoundField DataField="recordID" HeaderText="recordID" InsertVisible="False" ReadOnly="True" SortExpression="recordID" />
<asp:TemplateField>
<ItemTemplate>
<asp:CheckBox ID="chkPerson" runat="server" />
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="firstName" HeaderText="firstName" SortExpression="firstName" />
<asp:BoundField DataField="lastName" HeaderText="lastName" SortExpression="lastName" />
</Columns>
<HeaderStyle HorizontalAlign="Left" />
</asp:GridView>
<asp:AccessDataSource ID="AccessDataSource1" runat="server" DataFile="~/App_Data/gridviewCheckbox.mdb" SelectCommand="SELECT [recordID], [firstName], [lastName] FROM [record]"></asp:AccessDataSource>
<br />
<br />
<asp:Button ID="bttnMassUpdate" runat="server" OnClick="bttnMassUpdate_Click" Text="Mass Update" /><br />
</div>
</form>
</body>
</html>
For those of you who are unfamiliar with grid views, The DataKeyNames property is set to the PrimaryKey column of your datasource and in this example its the recordID column.
The OnDataBound and OnPageIndexChanging properties are set to the name of the functions I created that I want called when these events are fired.
I used a AccessDataSource for this example because It would allow anyone to download and run this example without the need to install a SQL server.
The data in this Access Database was generated with http://www.generatedata.com/.
Now since we have our aspx page setup we need to choose a data structure that can hold the primary key for each select row. I chose a List for this task.
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
List<int> list = new List<int>();
Session["gridSave"] = list;
}
}
Now when we go to another page we need a way to store the primary key of each row that has been selected and to also remove any key that has been unselected.
private void saveValues()
{
List<int> list = (List<int>)Session["gridSave"];
foreach (GridViewRow row in Gridview1.Rows)
{
int id = (int)Gridview1.DataKeys[row.RowIndex].Value;
bool chk = ((CheckBox)row.FindControl("chkPerson")).Checked;
if (chk)
{
//see if we have a id added already
if (list.Contains(id) == false)
{
list.Add(id);
}
}
else
{
if (list.Contains(id))
{
list.Remove(id);
}
}
}
Session["gridSave"] = list;
}
Everytime we go to a new page we will also have to see if any checkboxes need to be checked
private void loadValues()
{
List<int> list = (List<int>)Session["gridSave"];
foreach (GridViewRow row in Gridview1.Rows)
{
int id = (int)Gridview1.DataKeys[row.RowIndex].Value;
if (list.Contains(id))
{
CheckBox chkPerson = (CheckBox)row.FindControl("chkPerson");
chkPerson.Checked = true;
}
}
}
The above functions are called from the GridViews PageIndexChanging and OnDataBound Events.
protected void Gridview1_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
saveValues();
Gridview1.PageIndex = e.NewPageIndex;
}
protected void Gridview1_OnDataBound(object sender, EventArgs e)
{
loadValues();
}