SqlError.ToString Method   
Definition
Important
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Gets the complete text of the error message.
public:
 override System::String ^ ToString();public override string ToString();override this.ToString : unit -> stringPublic Overrides Function ToString () As StringReturns
The complete text of the error.
Examples
The following example displays each SqlError within the SqlErrorCollection collection.
public static void ShowSqlException(string connectionString)
{
    string queryString = "EXECUTE NonExistantStoredProcedure";
    using (SqlConnection connection = new SqlConnection(connectionString))
    {
        SqlCommand command = new SqlCommand(queryString, connection);
        try
        {
            command.Connection.Open();
            command.ExecuteNonQuery();
        }
        catch (SqlException ex)
        {
            DisplaySqlErrors(ex);
        }
    }
}
private static void DisplaySqlErrors(SqlException exception)
{
    for (int i = 0; i < exception.Errors.Count; i++)
    {
        Console.WriteLine("Index #" + i + "\n" +
            "Error: " + exception.Errors[i].ToString() + "\n");
    }
    Console.ReadLine();
}
Public Sub ShowSqlException(ByVal connectionString As String)
    Dim queryString As String = "EXECUTE NonExistantStoredProcedure"
    Using connection As New SqlConnection(connectionString)
        Dim command As New SqlCommand(queryString, connection)
        Try
            command.Connection.Open()
            command.ExecuteNonQuery()
        Catch ex As SqlException
            DisplaySqlErrors(ex)
        End Try
    End Using
End Sub
Private Sub DisplaySqlErrors(ByVal exception As SqlException)
    Dim i As Integer
    For i = 0 To exception.Errors.Count - 1
        Console.WriteLine("Index #" & i & ControlChars.NewLine & _
            "Error: " & exception.Errors(i).ToString() & ControlChars.NewLine)
    Next i
    Console.ReadLine()
End Sub
Remarks
The string is in the form "SqlError:", followed by the Message, and the stack trace. For example:
SqlError:UserId or Password not valid. <stack trace>