Trying to convert functional asp:CommandField to asp:LinkButton via asp:TemplateField - asp.net

Question

I want to take advantage of the breadth of attributes available to a LinkButton compared to a CommandField. When calling the code behind method from on click I get this error message:
CS0123: No overload for 'ViewHandler' matches delegate
'System.EventHandler'.
GridView definition:
<asp:GridView ID="wc" EmptyDataText="Empty WC table..." runat="server"
AutoGenerateColumns="False" GridLines="Horizontal" DataKeyNames="WC_ID,PW_ID,R_Qty"
CssClass="mGrid" PagerStyle-CssClass="pgr" AlternatingRowStyle-CssClass="alt"
AllowSorting="true" OnSorting="Sorting" AllowPaging="true" PageSize="15" ViewStateMode="Enabled"
OnSelectedIndexChanging="ViewHandler" OnPageIndexChanging="HandlePageIndexChanging" OnRowDataBound="gvRowDataBound"
OnRowEditing="gvRowEditing" OnRowCancelingEdit="gvRowCancelingEdit" OnRowUpdating="gvRowUpdating">
Orig button...
<asp:CommandField ControlStyle-Font-Size="Smaller" ControlStyle-ForeColor="#717171" HeaderText="..." ShowSelectButton="True" ItemStyle-HorizontalAlign="Center" SelectText="..." />
Convert to....
<asp:TemplateField HeaderText="..." ShowHeader="True" ItemStyle-HorizontalAlign="Center">
<ItemTemplate>
<asp:LinkButton style="font-size: 0.9em; color: #717171" ID="Details" runat="server" CausesValidation="False" OnClick="ViewHandler" CommandName="ViewHandler" Text="..." ToolTip="Click here to see purchase history and notes"></asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
Code behind:
protected void ViewHandler(object sender, GridViewSelectEventArgs e)
{
string WC_ID =wc.Rows[e.NewSelectedIndex].Cells[0].Text;
string PW_ID = wc.Rows[e.NewSelectedIndex].Cells[1].Text;
string VIN = wc.Rows[e.NewSelectedIndex].Cells[2].Text;
string PROD = wc.Rows[e.NewSelectedIndex].Cells[3].Text;
string W = wc.Rows[e.NewSelectedIndex].Cells[4].Text;
string SIZE = wc.Rows[e.NewSelectedIndex].Cells[5].Text;
e.Cancel = true;
Session.Add(WebConstants.WC_ID, WC_ID);
Session.Add(WebConstants.PW_ID, PW_ID);
Session.Add(WebConstants.VIN, VIN);
Session.Add(WebConstants.PROD, PROD);
Session.Add(WebConstants.W, W);
Session.Add(WebConstants.SIZE, SIZE);
DetailsNavigateMethod.DynamicInvoke();
HandlePageNavigation(WebConstants.WC_DETAILS, "WC View for WC_PurchaseID-> " + Session[WebConstants.WC_ID].ToString());
}
What do I need to do to make the signature match with the ViewHandler method? I did notice if I switch from GridViewSelectEventArgs to EventArgs the overload error goes away but then e.NewSelectedIndex does not exists...
Thanks!

Answer 1

Your problem is that the OnClick event handler for a LinkButton must have this signature:
protected void LinkButton_Click(Object sender, EventArgs e)
But you are defining it as
protected void ViewHandler(object sender, GridViewSelectEventArgs e)
However, you won't have access to e.NewSelectedIndex, obviously. What you can do is change your markup to (notice the CommandArgument part):
<asp:TemplateField HeaderText="..." ShowHeader="True" ItemStyle-HorizontalAlign="Center">
<ItemTemplate>
<asp:LinkButton style="font-size: 0.9em; color: #717171" ID="Details" runat="server" CausesValidation="False" OnClick="ViewHandler" CommandName="ViewHandler" CommandArgument='<%=string.Format("{0},{1},{2},{3}",Eval("Prop1"),Eval("Prop2"),Eval("Prop3"),Eval("Prop4")) %>' Text="..." ToolTip="Click here to see purchase history and notes"></asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
And your code to:
protected void LinkButton_Click(Object sender, EventArgs e)
{
string [] values = ((LinkButton)(sender)).CommandArgument.Split(new char[]{','});
//where values[0] will have WC_ID, values[1]=PW_ID, etc,
Session.Add(WebConstants.WC_ID, values[0]);
Session.Add(WebConstants.PW_ID, values[1]);//etc...
//Session.Add(WebConstants.VIN, VIN);
//Session.Add(WebConstants.PROD, PROD);
//Session.Add(WebConstants.W, W);
//Session.Add(WebConstants.SIZE, SIZE);
DetailsNavigateMethod.DynamicInvoke();
HandlePageNavigation(WebConstants.WC_DETAILS, "WC View for WC_PurchaseID-> " + Session[WebConstants.WC_ID].ToString());
}
Note:
Prop1, Prop2, etc. have to be changed to actual property names from your data source.
Above code hasn't been tested but that's the idea.