Application Exception Handler in WPF application

In WPF application I want to get all the exception in one place for that the below code will help you to capture all the exception in one place. It’s a global exception handling page. In the App.xaml file you need to specify the Startup and DispatcherUnhandledException method you need to give in XAML file. Global application exception handler or maintain application Error log to use below code.

This is the App.XAML file:

<Application x:Class="LiveSourceSample.App"

             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

             DispatcherUnhandledException="Application_DispatcherUnhandledException"

    Startup="Application_Startup"

             StartupUri="PreviewUI.xaml">

    <Application.Resources>

    </Application.Resources>

</Application>

In the App.XAML.CS file you need to add the Application start event and other exception event method need to create to capture the exceptions. The below code will help you to get application startup exception and other all the exception will be handled.

using System.IO;

using System.Windows.Forms;

public partial class App : Application
    {
        private void Application_Startup(object sender, StartupEventArgs e)
        {
            // UI Exceptions
            this.DispatcherUnhandledException += Application_DispatcherUnhandledException;

            // Thread exceptions
            AppDomain.CurrentDomain.UnhandledException += CurrentDomainOnUnhandledException;
        }

        private void Application_DispatcherUnhandledException(object sender, System.Windows.Threading.DispatcherUnhandledExceptionEventArgs e)
        {
            e.Handled = true;
            var exception = e.Exception;
            HandleUnhandledException(exception);
        }

        private void CurrentDomainOnUnhandledException(object sender, UnhandledExceptionEventArgs unhandledExceptionEventArgs)
        {
            HandleUnhandledException(unhandledExceptionEventArgs.ExceptionObject as Exception);
            if (unhandledExceptionEventArgs.IsTerminating)
            {
                Comman.ErrorLog("Application is terminating due to an unhandled exception in a secondary thread.");
            }
        }

        private void HandleUnhandledException(Exception exception)
        {
            string message = "Unhandled exception";
            try
            {
                AssemblyName assemblyName = System.Reflection.Assembly.GetExecutingAssembly().GetName();
                message = string.Format("Unhandled exception in {0} v{1}", assemblyName.Name, assemblyName.Version);
            }
            catch (Exception exc)
            {
                Comman.ErrorLog("Exception in unhandled exception handler - "+ exc.Message);
            }
            finally
            {
                Comman.ErrorLog(message+ exception.Message);
            }
        }
    }


Error Log Function:

 public class Comman
    {
 public static void ErrorLog(string sMessage)
       {
           StreamWriter objSw = null;
           try
           {
               string sFolderName = Application.StartupPath + @"\Logs\";
               if (!Directory.Exists(sFolderName))
                   Directory.CreateDirectory(sFolderName);
               string sFilePath = sFolderName + "Error.log";

               objSw = new StreamWriter(sFilePath, true);
               objSw.WriteLine(DateTime.Now.ToString() + " " + sMessage + Environment.NewLine);

           }
           catch (Exception ex)
           {
               Comman.ErrorLog("Error -" + ex.Message);
           }
           finally
           {
               if (objSw != null)
               {
                   objSw.Flush();
                   objSw.Dispose();
               }
           }
       }
}

How to delete duplicate rows from table in sql server?

One of my interviews asked this question. I have two columns Name and Age in my Table(MyTable). From the MyTable I want to delete only duplicate records. So the below Query will help you to delete or remove the duplicate rows from the MyTable.

Below is MyTable output:


SELECT * FROM MyTable

Current output:

Name    Age
vijay    30
antony    40
Aruna    28
antony    40
chander35
mark    42
vijay    30


Remove duplicate rows from the table:
The below query will help you to delete duplicate row from your table. Here we used Row_Number() function and PARTITION BY key words to remove the duplicate rows.

DELETE SUB FROM

(SELECT ROW_NUMBER() OVER (PARTITION BY Name, Age ORDER BY Name) cnt

 FROM MyTable) SUB

WHERE SUB.Cnt > 1

After the query execution the output is:


Name    Age
Aruna    28
antony    40
chander    35
mark    42
vijay    30


How to use Row_Number in SQL Select query:

SELECT ROW_NUMBER() OVER(ORDER BY Age) FROM mytable