DataSet

Hi Alan

I now get it 100%, thanks to you.:-)

Enjoy your day

There are only two situations where you can use the 'using' directive at the top of your program.

1. By far the most common is to follow 'using' by a namespace so that, when you use a class, struct or other type in that namespace in your code, you can do so without having to specify the namespace. For example:

using System;

using System.Windows.Forms;

So, if you want to use the DateTime struct which is in the System namespace, you can do this:

DateTime dt = new DateTime(2007, 1, 1);

rather than

System.DateTime dt = new System.DateTime(2007, 1 , 1);

2, The second (much rarer) use for the 'using' directive is to define an alias for a particular namespace or class. For example:

using DWORD = System.UInt32;

This allows you to use DWORD as an alias for System.UInt32 - the C# compiler simply replaces one with the other.

So, you'll gather from that, that the last two you've used are both wrong and unnecessary:

using datetime = System.Data.DateTime;

// it should be System.DateTime but pointless anyway as not saving any typing.

using c = System.ToString();

// wrong because you can only use the alias form with a namespace or a type. ToString() is a method and it has to be preceded by a type reference in any case, not by a namespace.

Hi Alan,

Thank you for taking your time to help with this problem.

Here is where my c came from: using System.Windows.Forms

                                                using datetime = System.Data.DateTime

                                                using c = System. ToString

Much appreciated.

Thanks

Taking the second problem first, I don't know what the types of the variables 'client', lstClient and 'c' are but I can see straight away that you've got some problems with at least some of these lines:

Bal = client.ToString();

Acc = client.ToString();

Br = client.ToString();

lstClient = client.ToString();

txtBal.Text = "R " + c.ToString(Bal);

txtBr.Text = c.ToString(Br);

The first three lines are definitely wrong because you've declared Bal,Acc and Br to be 'double' variables and you're trying to assign a string to them. If that string definitely contains a number, then the following should work:

double temp = double.Parse(client.ToString());

Acc = temp;

Br = temp;

lstClient looks like it might be a ListBox object. If so, then this line might be what you were trying to do:

lstClient.Text = client.ToString();

In the case of the last two lines, I suspect this is what you were trying to do though I don't know what 'c' represented:

The first problem about the DataSet is only a warning and won't stop your application from building but it sounds like you've either declared a DataSet variable and not used it or you've never initialized it by assigning an actual DataSet object to it.