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C# WinUI 3 Desktop Application Issue with ContentDialog and the XamlRoot

I am building a C# WinUI 3 desktop app running on Windows 10. I want to use a contentdialog to display error messages.
I am calling this method from multiple catch clauses:
private async void DisplayErrorDialog(string content)
{
ContentDialog ErrorDialog = new ContentDialog()
{
Title = "* Error *",
Content = content,
CloseButtonText = "Ok"
};
// XamlRoot must be set in the case of a ContentDialog running in a Desktop app
ErrorDialog.XamlRoot = this.Content.XamlRoot;
ContentDialogResult result = await ErrorDialog.ShowAsync();
}
Here is how I call the method:
catch (SqlException Sql_Error)
{
Debug.WriteLine($"Hello SQL error GetSQLData_App_View_Results_2020: {Sql_Error.Message}");
DisplayErrorDialog($"GetSQLData_App_View_Results_2020 (SQL Error): {Sql_Error.Message}");
}
catch (Exception Other_Error)
{
Debug.WriteLine($"Hello Other error GetSQLData_App_View_Results_2020: {Other_Error.Message}");
DisplayErrorDialog($"GetSQLData_App_View_Results_2020 (Other Error): {Other_Error.Message}");
}
}
I have many other contentdialogs working successfully within my application. I wanted/needed to test this error contentdialog so I explicitly threw an exception this way:
throw new Exception("SQL test exception #1");
The throw does work and the catch clause 'catches' the exception. However I am getting this error in the contentdialog:
Exception thrown at 0x00007FFFD5FE3FA9 (KernelBase.dll) in MetricReporting.exe: WinRT originate error - 0x80070057 : 'This element is already associated with a XamlRoot, it cannot be associated with a different one until it is removed from the previous XamlRoot.'.
I cannot figure this out. I am a beginner C# and WinUI 3 developer. Thank you for your help and guidance.
Thank you Andrew for your observation.
Here is more of my code:
public pageResults()
{
this.InitializeComponent();
Debug.WriteLine($"### --- InitializeComponents() Completed --- ###");
FetchSQLData_Ref_Metric();
FetchSQLData_Ref_Metric_MarketID();
FetchSQLData_StateCodes();
FetchSQLData_MetricYear();
FetchSQLData_Results();
Display_Results();
}
I am doing a lot of sql fetching of data into datatables and then I display the datatable in a datagrid on the page, which is part of a navigationview.
I inserted the 'throw' inside of a method that is inside of 'FetchSQLData_Results()'
private void FetchSQLData_Results()
{
string metricYear = string.Empty;
// Pre-load all views into their own separate datatables. Each views represents a metric year.
// At this time there are views for 2020, 2021, and 2022
foreach (DataRow row in dtMetricYear.Rows)
{
metricYear = row["metricyear"].ToString();
GetSQLData_App_View_Results_(metricYear);
}
}
private void GetSQLData_App_View_Results_(string metricYear)
{
// Load datatables with existing views
switch (metricYear)
{
case "2020":
GetSQLData_App_View_Results_2020();
break;
case "2021":
GetSQLData_App_View_Results_2021();
break;
case "2022":
GetSQLData_App_View_Results_2022();
break;
case "2023":
break;
case "2024":
break;
default:
break;
}
}
The throw is here:
public void GetSQLData_App_View_Results_2020()
{
try
{
using (SqlConnection con = new SqlConnection("Data Source = xxxx; Initial Catalog = xxxx; Integrated Security = True; Connect Timeout = 15; Encrypt = False; TrustServerCertificate = True; ApplicationIntent = ReadWrite; MultiSubnetFailover = False"))
{
**//throw new Exception("SQL test exception #1");**
//Prepare sql
//string sql = "select * from dbo.app_emb_prd_lvl_results_2020 order by metric_id";
string sql = "select * from app_emb_prd_lvl_results_2020 v join dbo.Ref_Metric r on v.metric_id = r.Metric_ID order by v.metric_id";
SqlCommand cmd = new SqlCommand(sql, con);
cmd.CommandType = System.Data.CommandType.Text;
//Open the connection
con.Open();
// Create adapter and fill the datatable with returned data from sql command
using (SqlDataAdapter adap = new SqlDataAdapter(cmd))
{
dtResults2020.Clear();
adap.Fill(dtResults2020);
try
{.. intentionally left blank ..}
catch (Exception List_Error)
{
Debug.WriteLine($"List error GetSQLData_App_View_Results_2020: {List_Error.Message}");
}
Debug.WriteLine($"GetSQLData_App_View_Results_2020 Completed");
} // end using sql adapter
} // end using sql connection
}
catch (SqlException Sql_Error)
{
Debug.WriteLine($"Hello SQL error GetSQLData_App_View_Results_2020: {Sql_Error.Message}");
DisplayErrorDialog($"GetSQLData_App_View_Results_2020 (SQL Error): {Sql_Error.Message}");
}
catch (Exception Other_Error)
{
Debug.WriteLine($"Hello Other error GetSQLData_App_View_Results_2020: {Other_Error.Message}");
DisplayErrorDialog($"GetSQLData_App_View_Results_2020 (Other Error): {Other_Error.Message}");
}
}

As I mentioned in the comments, XamlRoad might not be ready. Try fetching your data in Loaded instead of the constructor.
public pageResults()
{
this.InitializeComponent();
this.Loaded += pageResults_Loaded;
Debug.WriteLine($"### --- InitializeComponents() Completed --- ###");
}
private void pageResults_Loaded(object sender, RoutedEventArgs e)
{
FetchSQLData_Ref_Metric();
FetchSQLData_Ref_Metric_MarketID();
FetchSQLData_StateCodes();
FetchSQLData_MetricYear();
FetchSQLData_Results();
Display_Results();
}

How to return exception message with success value in C# windows application?

I am trying to return a success or failure value from one class to another. In case of failure, I also need to return the error message to the other class. How can this be achieved with a function returning integer?
clsDAL.cs
public int Insert(string name, string address)
{
try
{
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "sp_demo";
cmd.Parameters.Clear();
cmd.Parameters.AddWithValue("#id",1);
cmd.Parameters.AddWithValue("#name",name);
int i = cmd.ExecuteNonQuery();
return i;
}//try
catch(Exception e)
{
return -1; // Incase of failure need to return Exception error
}
}
clsBLL.cs
public int InsertData(string name, string address)
{
int i = dobj.InsertTable(name, address);
if (i == 1)
{
MessageBox.Show("Record Inserted successfully");
}
else
{
MessageBox.Show("Insertion failed"); // Show the exception message here
}
}

Move the try-catch blocks to the parent method so that you have the actual error message ready to be used.
Couple things to take care of, looking at your code...
Suggest to catch a more specific exception like SqlException type in addition to the generic exception. Specific exception types always give you more granular information on the error.
Ensure to close connection and dispose off relevant objects in a finally block as catch blocks shortcut your regular flow when exception occurs. using-statements would be much better as it is taken care implicitly.
Here is a sample edit for your code...
public int InsertData(string name, string address)
{
try
{
dobj.InsertTable(name, address);
MessageBox.Show("Record Inserted successfully");
}
catch (SqlException sqlException)
{
var messageBuilder= new StringBuilder();
messageBuilder.AppendLine(sqlException.Message);
foreach(SqlError sqlError in sqlException.Errors)
{
messageBuilder.AppendLine(sqlError.Message);
}
MessageBox.Show("Insertion failed with errors - " + messageBuilder.ToString());
}
catch (Exception exception)
{
MessageBox.Show("Insertion failed with errors - " + exception.Message);
}
}

SqlException not caught in Winforms

I got this code:
try
{
using (SqlConnection sourceCnx = new SqlConnection(SOURCE_CONN_STRING))
{
sourceCnx.Open();
SqlCommand sysCmd = sourceCnx.CreateCommand();
sysCmd.CommandText = "My query";
sysCmd.ExecuteNonQuery();
}
}
catch (Exception)
{
//Throwing a message box informing that there is an error
}
I want to display a message when the user is no longer connected to the internet.
But when I debug my program without an internet connection, the program crashes with a SqlException. (The "catch" block does not catch the exception)
I tried to add catch (SqlException) { // code } before catch (Exception) but it doesn't work.
I still have an exception instead of a message displayed by the catch block.
I don't know what to do because if I create a method to test the internet connection (try to ping google.com) then return true if it's ok, it will be the same : I got an exception because of no internet connection.
Any idea?

You have set your environment to always break when a CLR exception is thrown. You can leave it like that if you wish and press F5 to carry on execution of your program. Or you can turn this off (it is switched off by default):
Go to Debug menu, select Exceptions and ensure Common Language Runtime Exceptions is not checked.

You might want to put the exception handing inside the using block, like this:
using (SqlConnection sourceCnx = new SqlConnection(SOURCE_CONN_STRING))
{
try
{
sourceCnx.Open();
SqlCommand sysCmd = sourceCnx.CreateCommand();
sysCmd.CommandText = "My query";
sysCmd.ExecuteNonQuery();
}
catch (SqlException e)
{
// This will catch any SQL Exceptions.
// Use "throw;" if you want to rethrow the exception up the stack
}
catch (Exception e)
{
// This will catch any other exceptions.
// Use "throw;" if you want to rethrow the exception up the stack
}
}
Assuming that you have actually replaced "My Query" with something specific to your scenario, the SqlException is most likely down to your machine not being able to see the SQL Server instance. Try pinging it...

Try with this:
try
{
using (SqlConnection sourceCnx = new SqlConnection(SOURCE_CONN_STRING))
{
sourceCnx.Open();
SqlCommand sysCmd = sourceCnx.CreateCommand();
sysCmd.CommandText = "My query";
sysCmd.ExecuteNonQuery();
}
}
catch(SqlException sqlEx)
{
MessageBox.Show("there was a sql issue");
}
catch(Exception ex)
{
MessageBox.Show("there was some other issue");
}

In the part of the catch code, you have to set a variable not? And after that take any of her property.
For example:
try
{
using (SqlConnection sourceCnx = new SqlConnection(SOURCE_CONN_STRING))
{
sourceCnx.Open();
SqlCommand sysCmd = sourceCnx.CreateCommand();
sysCmd.CommandText = "My query";
sysCmd.ExecuteNonQuery();
}
}
catch (Exception ex)
{
//example
MessageBox.show(ex.message);
}

I think you should get the BaseException
catch (Exception exp)
{
if (exp.GetBaseException() is System.Data.SqlClient.SqlException)
{
var sqlException = exp.GetBaseException() as System.Data.SqlClient.SqlException;
if (sqlException != null && sqlException.Number == 547)
{
//do something
}
}
//do something
}

Calling a MySQL Routine in C#

Please accept my apologies if I'm getting my verbiage wrong; I'm just now learning C# (my background is mostly Visual Basic and PHP).
What I'm trying to do is create a class / routine in C# (Windows Forms) for connecting and disconnecting to a MySQL database that can then be reused throughout the rest of my project without having to reiterate the code every time.
I've got my class / routine setup, but I'm stuck on trying to call it from the rest of my project. I know in Visual Basic this was a fairly simple task to do, but I just can't seem to figure it out how to do it in C#.
Any suggestions? Thank you in advance.
public void dbDisconnect(object sender, EventArgs e)
{
try
{
MySqlConnection connection = new MySqlConnection(Properties.Settings.Default.mysql_db_conn_string);
connection.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}

Here's a method I currently have in my app:
public static MySqlConnection CreateConnection(
string mysqlServer,
string mysqlUser,
string mysqlPassword,
string mysqlDatabase)
{
MySqlConnection mysqlConnection = null;
string mysqlConnectionString = String.Format(
"server={0};uid={1};pwd={2};database={3};DefaultCommandTimeout={4};",
mysqlServer, mysqlUser, mysqlPassword, mysqlDatabase, 120);
/**
** Workaround for MySQL 5.6 bug:
** http://stackoverflow.com/questions/30197699/reading-from-stream-failed-mysql-native-password-error
*/
int tryCounter = 0;
bool isConnected = false;
do
{
tryCounter++;
try
{
mysqlConnection = new MySqlConnection();
mysqlConnection.ConnectionString = mysqlConnectionString;
mysqlConnection.Open();
if (mysqlConnection.State == ConnectionState.Open)
{
isConnected = true;
}
}
catch (MySqlException ex)
{
if (tryCounter < 10)
{
DebugLog.Dump(ex.ToString(), DebugLog.MainLogFilePath);
Thread.Sleep(10000); // 10 seconds.
}
else
{
throw;
}
}
} while (!isConnected);
return mysqlConnection;
}
Usage:
using (MySqlConnection hostsDbConnection = HostsDbConnector.CreateConnection())
{
// Do something...
}
With using keyword you don't need to close the connection manually, it'll be closed automatically when it's no longer needed.

Inner Exceptions C#

Story: I've 3 functions from 3 different classes. Functions calling order is:
Form1_Load(...) -> Student.GetAllStudents(...) -> StudentDAL.GetStudentInformation(...) -> ConnectionManager.GetConnection(...)
What I want to do is to display StackTrace of the inner most function i.e. ConnectionManager.GetConnection(), in a MessageBox in Form1 class. In other words I don't want to use MessageBox in any inner classes, but only in outer most class that is Form1 class.
Problem: To get inner exceptions we can use InnerException or GetBaseException() etc. but when I try to get inner exception it throws an exception "Object reference not set to an instance", meaning that there is no inner exception and, when I check, the value is also null. All I want to know here why it's null? Shouldn't it be holding reference to the inner exception? Correct me if I'm wrong.
Function codes :
Form1_Load(...)
private void Form1_Load(object sender, EventArgs e)
{
try
{
DataTable dt = new DataTable();
dt.Load((**new Student().GetAllStudents()**));
if (dt.Rows.Count <= 0)
{
MessageBox.Show("Student table empty.");
}
else
{
this.dataGridView1.DataSource = dt;
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message+Environment.NewLine+"Source(s) : "+ex.StackTrace.Substring(0, ex.StackTrace.LastIndexOf("at")));
}
GetAllStudents(...)
public SqlDataReader GetAllStudents()
{
try
{
return StudentInformationDataAccessLayer.GetStudentInformation();
}
catch (Exception ex)
{
throw ex;
}
}
GetStudentInformation(...)
public static SqlDataReader GetStudentInformation()
{
try
{
SqlConnection sqlCon = null;
sqlCon = ConnectionManager.GetConnection();
if (sqlCon == null)
{
return null;
}
String Query = null;
Query = "SELECT * FROM [dbo].[Student]";
SqlCommand cmd = new SqlCommand(Query, sqlCon);
SqlDataReader dr = null;
dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
return dr;
}
catch (Exception ex)
{
throw ex;
}
}
GetConnection(...)
public static SqlConnection GetConnection()
{
String _connectionString = null;
_connectionString = ConfigurationManager.ConnectionStrings["Default"].ConnectionString;
if (_connectionString == null)
{
return null;
}
try
{
SqlConnection connection = new SqlConnection(_connectionString);
connection.Open();
return connection;
}
catch (Exception ex)
{
throw ex;
}
}

If you want stack trace and exception information to be preserved, you should change the code that re-throws caught exceptions like this:
}
catch(Exception ex)
{
// do what you need to do with ex
// ..
// rethrow..
throw; // notice this is not "throw ex";
}
Re-throwing the exception using just throw; preserves the original stack trace. There won't necessarily be an inner exception but that's not what you should care about. What you need to know is the stack trace of where the exception originated.

If you want to re-throw with inner exception set, use below code, but remember that you will lose stack trace:
try
{
...
}
catch (Exception ex)
{
throw new Exception("message", ex);
}
To just re-throw an exception and preserve stack trace, use:
try
{
...
}
catch (Exception ex)
{
throw;
}

Not every exception do actually have an inner exception. First check if inner ex is a null and if it is not then process it.
Having said this, you can of course re-throw your exception like below:
catch(Exception ex)
{
// so smth
// ..
// rethrow..
throw;
}
But please remember two things:
Do not type throw ex, just throw.
Do it only if you really want to do something with this exception before rethrowing. If you don't have such a plan, just don't catch it on this level.

I would do something like:
try
{
...
}
catch (Exception ex)
{
if (ex.InnerException == null)
throw ex;
else
throw ex.InnerException;
}
then at some point where you want to do the stack trace, do something along the lines of:
StackTrace trace = new StackTrace(System.Threading.Thread.CurrentThread, true);
StackFrame[] frames = trace.GetFrames();
string result = string.Empty;
foreach (StackFrame sf in frames)
{
string += sf.GetMethod().Name;
}
MessageBox(result);