DataSet

Question

1. M using Visual Studio 2005 and I keep getting this warning in C# that The Variable 'DataSet1' is either undeclared or was never assigned. How do I solve that?

2.

private void btnDep_Click(object sender, EventArgs e)

{

try

{

if (txtAccNum.Text != "" && txtBal.Text != "" && txtBr.Text != "" && lstClient.Text != "")

{

double Bal, Acc, Br;

BillionBanking client = new BillionBanking();

Bal = client.ToString();

Acc = client.ToString();

Br = client.ToString();

lstClient = client.ToString();

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

txtBr.Text = c.ToString(Br);

}

else

{

MessageBox.Show("Select The Correct Number!!");

}

catch (Exception client)

{

MessageBox.Show(client.Message.ToString());

}

From the above code I keep getting errors "Cannot implicitly convert type 'string' to 'double'. I have been advised to double.Parse yet it still doesn't work.

Thanks for your time!!

Ntsibi B · Answer

Hi Alan I now get it 100% thanks to you.:-) Enjoy your day

Alan · Answer

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.

Ntsibi B · Answer

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

Alan · Answer

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 BalAcc 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()); Bal = temp; 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: txtBal.Text = R  + Bal .ToString(); txtBr.Text = Br .ToString(); 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.