CODEWITHSUNDEEP
vb.net
BAS
BAS

Reputation: 33

Keeping Dim value after if statement

I've been programming for about two months now. I have a problem with keeping a dim value after an if statement. I have a loop that if doesn't add up to 100 (it is for a percentage) stops entering in a radgrid. My work around for this is to store the value in a textbox but this hardly seems efficient. So how do i store this value in memory as opposed to in a textbox. Here is the code.

    Dim p As Integer = RadGridView1.CurrentRow.Index - 1    
        Try    
            For int1 = p To 0 Step -1
                If RadGridView1.Rows(Row).Cells(1).IsCurrent AndAlso Me.RadGridView1.IsInEditMode AndAlso RadGridView1.ActiveEditor.Value <> 0 Then   
                    If RadGridView1.Rows(int1).Cells(1).Value <> Nothing Then Exit For
                    Dim total As String = 0
                    total += RadGridView1.Rows(int1).Cells("PC").Value

                    Dim int2 As Integer
                    int2 += RadGridView1.Rows(int1 - 1).Cells("PC").Value

`this  is my problem here i want this dim value after the if statement    
    Dim percenttotal = int2 + RadGridView1.Rows(Row - 1).Cells("PC").Value

'my workaround is to keep the value in a textbox
    TextBox3.Text = int2 + RadGridView1.Rows(Row - 1).Cells("PC").Value

                End If
            Next

            If RadGridView1.Rows(Row).Cells(1).IsCurrent AndAlso Me.RadGridView1.IsInEditMode AndAlso RadGridView1.ActiveEditor.Value <> 0 Then

' i want this code to be the above dim value not to come from a textbox             
      If TextBox3.Text <> 100 Then
                    MsgBox("Your % above does not equal 100", MsgBoxStyle.Critical, "Value Error")
                    e.Cancel = True
                End If
            End If

Upvotes: 0

Views: 836

Answers (2)

Jeremy
Jeremy

Reputation: 4838

You are likely running into variable scoping issues.

Consider the following code:

Public Class Form1


    Dim counter As Integer

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim i As Integer
    i += 1
    counter += 1

    MsgBox("i: was clicked " & i & " times!" & vbCrLf & "counter: was clicked " & counter & " times!")
End Sub
End Class

i is defined within the function, and therefore will have its value reset each time the function is called.

counter is defined as the class or module level, so it retains its value in between function calls and its value is persistent until the form closes.

See: https://msdn.microsoft.com/en-us/library/ms973875.aspx

Edit: The other folks are more correct in that a variable defined with a "block" like If, For, While, etc. will have the scope of that block.

See: https://msdn.microsoft.com/en-us/library/1t0wsc67.aspx

Upvotes: 0

Bradley Uffner
Bradley Uffner

Reputation: 16991

You are having a problem with Scope. I like to think of Scope as a set of boxes, like those nesting Russian dolls. You can keep smaller boxes inside other boxes. A new Scope gets created and placed INSIDE the previous scope every time code enters a Sub , function , loop , and a few other cases. When you declare a variable it is placed in the current scope. Your code will be able to access the variables from any scope that it is currently inside, but it can't see any variables that are declared inside the smaller scopes inside it. Your code "can see out, but not in".

The problem that you are having is that you are declaring your variable inside the "If" scope, and when it hits the "End If" that scope goes away, taking your variable with it. The solution is to declare your variable at a higher scope so that it sticks around for the entire time you need it. Try declaring your variable BEFORE the "If" and setting it's value inside.

BTW, this is also why the form controls work for storing your data. They exist at a very high scope, the lifetime of the form instance.

You can read more about how scope works in VB.NET here https://msdn.microsoft.com/en-us/library/1t0wsc67.aspx

Upvotes: 1

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