Why can't my LinkButton inside the GridView trigger an OnClick event?

Question

I have a LinkButton inside a GridView (via TemplateField). No matter what I try, LinkButton will not reference the event handler. I tried both:

• Traditional event handler ("OnClick")
• OnRowCommand event handler at the GridView level.

In both cases, I debugged and did not even catch the event handler.

If I move LinkButton on the page (so it's not in the GridView), it works fine, so I know the syntax is right.

Here is the "traditional" method:

<asp:TemplateField> <ItemTemplate> <asp:LinkButton Text="Cancel" ID="DeleteButton" CausesValidation="false" OnClick="CancelThis" runat="server" /> </ItemTemplate> <asp:TemplateField> 

Interestingly, if I remove the "CancelThis" method from the code behind, it throws an error. Therefore, I know that he knows about his event handler because he is looking for it at compilation.

Here is the RowCommand method:

 <asp:TemplateField> <ItemTemplate> <asp:LinkButton Text="Cancel" ID="DeleteButton" CausesValidation="false" CommandName="CancelThis" runat="server" /> </ItemTemplate> <asp:TemplateField> 

In this case, the GridView has:

 OnRowCommand="GridView_RowCommand" 

He puts off, but never hints that he is raising an event.

Any idea what I'm missing here?

Answer 1

How do you bind your GridView ? Do you use data source control? If you contact manually during Page_Load , it is possible that, since the grid is bound to each round trip, the event handler is not caught properly. If so, you can try something like:

 protected void Page_Load(object sender, EventArgs e) { if(!Page.IsPostBack) { //do binding } } 

Can you post a sample anchor code to jump with your markup?

If you decide to really fix the problem, you can connect to the RowDataBound event in the Grid, find the button manually and add the handler to the code behind. Something like:

markup fragment:

 <asp:GridView ID="gvTest" runat="server" OnRowDataBound="gvTest_RowDataBound" /> 

code behind:

 protected void gvTest_RowDataBound(object sender, GridViewRowEventArgs e) { if(e.Row.RowType == DataControlRowType.DataRow) { //find button in this row LinkButton button = e.Row.FindControl("DeleteButton") as button; if(button != null) { button.Click += new EventHandler("DeleteButton_Click"); } } } protected void DeleteButton_Click(object sender, EventArgs e) { LinkButton button = (LinkButton)sender; // do as needed based on button. } 

I'm not sure what the purpose of the button is, but assuming it is a line delete button, you may not want to use this approach as in an event handler, you do not have direct access to the line in the question, how would you use the RowCommand event.

Is there a reason you are using the Template field? Vs say a ButtonField ? If you use ButtonField , you can connect to the RowCommand event.

markup fragment:

 <asp:GridView ID="gvTest" runat="server" OnRowCommand="gvTest_RowCommand"> <columns> <asp:buttonfield buttontype="Link" commandname="Delete" text="Delete"/> .... </columns> </asp:GridView> 

code behind:

 protected void gvTest_RowCommand(object sender, GridViewCommandEventArgs e) { if(e.CommandName == "Delete") { //take action as needed on this row, for example int rowIndex = Convert.ToInt32(e.CommandArgument); GridViewRow currentRow = (sender as GridView).Rows[rowIndex]; //do something against the row... } } 

You might want to check out the MSDN docs on some of these topics:

• RowcommandEvent
• class ButtonField

EDIT:

To answer your question on ButtonField - yes, I don’t understand why you couldn’t still deal with the button field. Here's a snippet to find the button field during row data and hide it (unchecked, but I think it will work ...)

 protected void gvTest_RowDataBound(object sender, GridViewRowEventArgs e) { if (e.Row.RowType == DataControlRowType.DataRow) { //let assume your buttonfield is in column 1 // (you'd know this based on your markup...) DataControlFieldCell cell = e.Row.Cells[1] as DataControlFieldCell; if(cell != null) { ButtonField field = cell.ContainingField as ButtonField; //based on your criteria, show or hide the button field.Visible = false; //or field.Visible = true; } } } 

Answer 2

Is viewing enabled in your GridView? It often turned me on.

Answer 3

 <button onclick="window.open('<%#Eval("ReportLinks")%>', '_blank');" title='<%#Eval("ReportLinks")%>'> Link</button>