How to display an error message in an ASP.NET Web Application [duplicate]
-
19-08-2019 - |
Question
I have an ASP.NET web application, and I wanted to know how I could display an error message box when an exception is thrown.
For example,
try
{
do something
}
catch
{
messagebox.write("error");
//[This isn't the correct syntax, just what I want to achieve]
}
[The message box shows the error]
Thank you
Duplicate of How to display an error message box in a web application asp.net c#
Solution
Roughly you can do it like that :
try
{
//do something
}
catch (Exception ex)
{
string script = "<script>alert('" + ex.Message + "');</script>";
if (!Page.IsStartupScriptRegistered("myErrorScript"))
{
Page.ClientScript.RegisterStartupScript("myErrorScript", script);
}
}
But I recommend you to define your custom Exception and throw it anywhere you need. At your page catch this custom exception and register your message box script.
OTHER TIPS
The errors in ASP.Net are saved on the Server.GetLastError property,
Or i would put a label on the asp.net page for displaying the error.
try
{
do something
}
catch (YourException ex)
{
errorLabel.Text = ex.Message;
errorLabel.Visible = true;
}
All you need is a control that you can set the text of, and an UpdatePanel if the exception occurs during a postback.
If occurs during a postback: markup:
<ajax:UpdatePanel id="ErrorUpdatePanel" runat="server" UpdateMode="Coditional">
<ContentTemplate>
<asp:TextBox id="ErrorTextBox" runat="server" />
</ContentTemplate>
</ajax:UpdatePanel>
code:
try
{
do something
}
catch(YourException ex)
{
this.ErrorTextBox.Text = ex.Message;
this.ErrorUpdatePanel.Update();
}