Unique Index

You can also include the custom error message in a THROW statement

BEGIN TRY
    INSERT INTO Students (StudentID, Name, Age) VALUES (123, 'John Doe', 25);
END TRY
BEGIN CATCH
    IF ERROR_NUMBER() = 2601
    BEGIN
        THROW 50000, 'Duplicate record found', 1;
    END
END CATCH

Lets say you have a table named Students with a unique index on the StudentID field. You can catch the unique index violation error using a TRY...CATCH block in your SQL query like this

BEGIN TRY
    INSERT INTO Students (StudentID, Name, Age) VALUES (123, 'John Doe', 25);
END TRY
BEGIN CATCH
    IF ERROR_NUMBER() = 2601
    BEGIN
        RAISERROR('Duplicate record found', 16, 1);
    END
END CATCH

if the INSERT statement violates the unique index on the StudentID field, the error number 2601 will be raised. The IF condition in the CATCH block checks for this error number and raises a custom error message using the RAISERROR statement. 

You can catch the unique index violation error in your SQL query and replace the standard error message with your own custom error message.

Hi AMit

  It is giving message ex does not contain a definition for number

Thanks

Hi Ramco,

Do refer below link which shows complete implementaion 

https://www.codeproject.com/Articles/1130113/Best-Ways-of-Implementing-Uniqueness-or-Unique-Key

else

try
{

}
catch(SqlException ex)
{
   if(ex.Number == 2601 || ex.Number == 2627)
   {
      // Violation in one on both...
       lblErrorMessage.text = "Duplicate record found";
   }
}


OR

try
{

}
catct(Exception ex)
{
if(ex.Message.Contains("UNIQUE KEY constraint"))
   lblErrorMessage.text="[your unique field] is insert before.";
}

Try this

try
{
    // Your code to insert a record into the database
}
catch (SqlException ex)
{
    if (ex.Number == 2601) // Check if the error is due to a unique index violation
    {
        // Display your custom error message
        Console.WriteLine("Duplicate record found");
    }
    else
    {
        // Handle other exceptions as needed
        Console.WriteLine("An error occurred: " + ex.Message);
    }
}