Show message on click of a button in ASP.net

I have a Gridview, a label and a Button in ASP.net. If the total number of records in the g开发者_如何学Goridview is more than 500 and if the user clicks on the button, a message "You cannot print more than 500 records at one time".

How can I do this in ASP.net. If it is less than 500 it is currently generating a PDF.

Thanks

Like this:

if (grid.Rows.Count > 500) {
    label.Text = "You cannot print more than 500 records at one time";
} else {
    //Export a PDF
}

If this doesn't answer your question, please provide more detail.

I think you'd want something like this in the code behind file:

protected void Button_Click(object sender, EventArgs e)
{
    if (this.myGridView.Rows.Count > 500)
    {
        this.myLabel.Text = "You can not print more than 500 records";
    }
    else
    {
         // Print the PDF
    }
}

Now on the ASP side of things you hook these up like so:

<asp:button id="myButton" onclick="Button_Click" runat="server" text="Print PDF of Grid" />

When you get your records, examine the count of the records. Then, if it's more than 500, add a javascript alert to the button like this:

If records.Count > 500 Then
  btnPrint.Attributes("onclick") = "alert('You cannot print more than 500 records at one time.'); return false;"
Else
  btnPrint.Attributes("onclick") = ""
End If