Checking All CheckBoxes in a GridView

Checking All CheckBoxes in a GridView

Here's the part which shows how to implement client-side JavaScript checking/unchecking
C#:
protected void Page_Load(object sender, System.EventArgs e)
{

// DataBind GridView here
//...

'On every page visit we need to build up the CheckBoxIDs array
foreach(GridViewRow row in grid.Rows)
{

//Get a programmatic reference to the CheckBox control
CheckBox chk = (CheckBox)row.FindControl("chk");
ClientScript.RegisterArrayDeclaration("CheckBoxIDs", string.Concat("'", chk.ClientID, "'"));

}

}

JavaScript:
<script type="text/javascript">

function ChangeCheckBoxState(id, checkState)
{

var cb = document.getElementById(id);
if (cb != null)
cb.checked = checkState;

}

function ChangeAllCheckBoxStates(checkState)
{

// Toggles through all of the checkboxes defined in the CheckBoxIDs array
// and updates their value to the checkState input parameter
if (CheckBoxIDs != null)
{
for (var i = 0; i < CheckBoxIDs.length; i++)
ChangeCheckBoxState(CheckBoxIDs[i], checkState);
}

}

</script>

...

<input type="button" value="Check All" onclick="ChangeAllCheckBoxStates(true);" />
 
<input type="button" value="Uncheck All" onclick="ChangeAllCheckBoxStates(false);" />