Read from database error but no error message

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Hi there, I have a problem where visual studio throws no error but the code does. When the try and catch statements are inplace they throw back the error and the program stops. However when I take out the try and catch the program loads etc but the code does do as I am expecting. I may be looking at this in a totally unorthadox way and thats the problem but to me it looks like it should work.

Below is the sql code section and also how I am calling it.

public void getUser()
       {
           SqlConnection conn = new SqlConnection(Calorie_Counter_UK.Properties.Settings.Default.Calorie_CounterConnectionString);
           conn.Open();
         try
          {
               using (SqlCommand command = new SqlCommand("SELECT * FROM [User] LIMIT 1",conn))
               {
                   SqlDataReader reader = command.ExecuteReader();
                   while (reader.Read())
                   {
                       name = reader.GetString(0);
                       age = reader.GetInt16(1);
                       height = reader.GetInt16(2);
                       weight = reader.GetDecimal(3);
                       target = reader.GetDecimal(4);
                   }
               }
         }
         catch
        {
             MessageBox.Show("Problem with update");
        }
       }
       public string getName()
       {
           return name;
       }
       public int getAge()
       {
           return age;
       }
       public int getHeight()
       {
           return height;
       }
       public decimal getWeight()
       {
           return weight;
       }
       public decimal getTarget()
       {
           return target;
       }

private void Window_Loaded(object sender, RoutedEventArgs e)
       {
           User_database user = new User_database();
           user.getUser();
           txtName.Text = user.getName();
           nudAge.Value = user.getAge();
           nudHeight.Value = user.getHeight();
           nudWeight.Value = Convert.ToDouble(user.getWeight());
           nudTargetWeight.Value = Convert.ToDouble(user.getTarget());
       }

It is frustrating me a little bit because I can't get an error message to even help me along! If someone could shed some light it would be appreciated!

Dan

Posted 1-Aug-11 1:36am

DanHodgson88

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walterhevedeich 1-Aug-11 7:39am

Sounds weird. But have you tried catching the actual exception and then putting it in your messagebox? It might be helpful if we can see the actual error.

Herman<T>.Instance 1-Aug-11 7:40am

you use the SqlConection object which is for MS Sql Server and you use a MySQL query (LIMIT 1 should be TOP 1 in T-SQL )

[no name] 1-Aug-11 7:42am

Nice catch!!!

Herman<T>.Instance 1-Aug-11 7:47am

thank you

[no name] 1-Aug-11 7:42am

Either log/display the exception in the catch block or remove the try/catch altogether and see what exception it throws.

5 solutions

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#realJSOP · Accepted Answer · 2011-08-01T01:40:00

Solution 1

Why aren't you putting the SqlConnection stuff inside the try block?

I would step through it with the debugger to see what's happening.

Posted 1-Aug-11 1:40am

#realJSOP

Comments

DanHodgson88 1-Aug-11 9:11am

John, To be honest with you im pretty new at this so using try and catch blocks doesn't come naturally to me yet so me putting it in the wrong place doesn't surprise me! I will alter the code to ensure the sqlconnection and other bits nad bobs are within the try catch :)

Herman<T>.Instance · Accepted Answer · 2011-08-01T01:46:00

This code should tell you what the problem might be:

C#

public void getUser()
{
	SqlConnection conn = new SqlConnection(Calorie_Counter_UK.Properties.Settings.Default.Calorie_CounterConnectionString);
	using (SqlCommand command = new SqlCommand("SELECT TOP 1 * FROM [User] ",conn))
	{
		try
		{
			command.Connection.Open();
			SqlDataReader reader = command.ExecuteReader();
			while (reader.Read())
			{
				name = reader.GetString(0);
				age = reader.GetInt16(1);
				height = reader.GetInt16(2);
				weight = reader.GetDecimal(3);
				target = reader.GetDecimal(4);
			}
		}
		catch (Exception err)
		{
			MessageBox.Show(err.ToString()); // provide that message in 
		}
		finally
		{
			if (command.Connection.State.Equals(ConnectionState.Open))
			{
				command.Connection.Close();
				command.Connection.Dispose();
			}
		}
	}
}

Shameel · Accepted Answer · 2011-08-01T01:46:00

You have not mentioned what database it is. If it is SQL Server (as you have used SqlConnection class) then, as digimanus suggested, rewrite your query as

SQL

SELECT TOP 1 * FROM [User]

There is no LIMIT clause in MS SQL Server.

If you database is indeed MySQL, then use the appropriate Library to access the database, you cannot use SqlConnection in that case.

And your try/catch code is horrible. If at all you use try/catch, use the catch block to log the actual exception message.

Wonde Tadesse · Accepted Answer · 2011-08-01T01:48:00

Solution 4

This probably happens due to LIMIT key word. If you are using SQL Server, it might not support the key word. Take a look at this Channel 9 discussion. SQL Server and LIMIT clauses on SELECT statements[^]

Posted 1-Aug-11 1:48am

Wonde Tadesse

Comments

DanHodgson88 1-Aug-11 9:06am

spot on thanks :)

Wonde Tadesse 3-Aug-11 21:26pm

Thanks.

Mohammad A Rahman · Accepted Answer · 2011-08-01T01:52:00

It might be helpful,

sql_top[^]

I tried with following code and it works,

C#

public static void getUser()
       {
           SqlConnection conn = new SqlConnection(@"YOU CONNECTION STRING");
           conn.Open();
           try
           {
               using (SqlCommand command = new SqlCommand("SELECT Top 1 * FROM [YOURTABLENAME]", conn))
               {
                   SqlDataReader reader = command.ExecuteReader();
                   while (reader.Read())
                   {
                       var name = reader.GetString(0);
                       var age = reader.GetInt16(1);
                       var height = reader.GetInt16(2);
                       var weight = reader.GetDecimal(3);
                       var target = reader.GetDecimal(4);
                   }
               }
           }
           catch
           {
               Console.WriteLine("Problem with update");
           }
       }
   }

:)

Read from database error but no error message

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