[SIM-1895121]

I am currently working on a project called TG automotive. It is a simple form with pretty basic calculations. I have the program running flawlessly except for the validation. I am supposed to have a function that tests to make sure inputs are numeric and not negative. I have written the function, i just cannot seem to figure out how to actually implement it in the program. Any tips or suggestions greatly appreciated.  The ValidateInputs() is the function i created that i need to implement. Here is the full code.

Code

Public Class Form1
   Private Sub GroupBox5_Enter(sender As Object, e As EventArgs) Handles GroupBox5.Enter

   End Sub

   Private Sub Label11_Click(sender As Object, e As EventArgs) Handles Label11.Click

   End Sub

   Function CalcOilAndLube() As Decimal
       Dim decOil As Decimal
       If chkOilChange.Checked = True Then
           decOil += 36
       End If
       If chkLube.Checked = True Then
           decOil += 28
       End If
       Return decOil
   End Function
   Function Misc() As Decimal
       Dim decMisc As Decimal
       If chkInspection.Checked = True Then
           decMisc += 15
       End If
       If chkMuffler.Checked = True Then
           decMisc += 200
       End If
       If chkTireRotation.Checked = True Then
           decMisc += 20
       End If
       Return decMisc
   End Function
   Function RadandTran() As Decimal
       Dim decRadcCost As Decimal
       If chkRadFlush.Checked = True Then
           decRadcCost += 50
       End If
       If chkTranFlush.Checked = True Then
           decRadcCost += 120
       End If
       Return decRadcCost
   End Function
   Function Parts() As Decimal

       Dim decParts As Decimal
       decParts = FormatCurrency(txtParts.Text)
       Return decParts
   End Function
   Function Labor() As Decimal
       Dim decLabor As Decimal
       decLabor = FormatCurrency(txtLabor.Text)
       Return decLabor
   End Function
   Function Tax() As Decimal
       Dim dectax As Decimal
       dectax = FormatCurrency(txtParts.Text) * 0.06
       Return dectax

   End Function


   Private Sub btnClear_Click(sender As Object, e As EventArgs) Handles btnClear.Click
       ClearMisc()
       ClearOil()
       ClearOther()
       ClearPartsAndLabor()
       ClearRad()
   End Sub

   Private Sub btnCalculate_Click(sender As Object, e As EventArgs) Handles btnCalculate.Click


       Dim decParts As Decimal
       Dim decService As Decimal
       Dim decTax As Decimal
       Dim decTotal As Decimal
       decService = CalcOilAndLube() + Misc() + RadandTran() + Labor()
       decParts = Parts()
       decTax = Tax()
       decTotal = FormatCurrency(decService + decParts + decTax)
       lblParts.Text = FormatCurrency(decParts)
       lblServicesAndLabor.Text = FormatCurrency(decService)
       lblTax.Text = FormatCurrency(decTax)
       lblTotal.Text = FormatCurrency(decTotal)

   End Sub
   Sub ClearOil()
       chkOilChange.Checked = False
       chkLube.Checked = False

   End Sub
   Sub ClearRad()
       chkRadFlush.Checked = False
       chkTranFlush.Checked = False

   End Sub
   Sub ClearMisc()
       chkInspection.Checked = False
       chkMuffler.Checked = False
       chkTireRotation.Checked = False
   End Sub
   Sub ClearPartsAndLabor()
       txtLabor.Text = String.Empty
       txtParts.Text = String.Empty
   End Sub
   Sub ClearOther()
       lblParts.Text = String.Empty
       lblServicesAndLabor.Text = String.Empty
       lblTax.Text = String.Empty
       lblTotal.Text = String.Empty
   End Sub
   Private Sub btnExit_Click(sender As Object, e As EventArgs) Handles btnExit.Click
       Me.Close()
   End Sub
   Function ValidInputs() As Boolean
       Dim decVal1 As Decimal
       Dim decVal2 As Decimal
       If Not Decimal.TryParse(txtParts.Text, decVal1) Then
           MessageBox.Show("Enter a Numeric value please")
           Return False
       End If
       If decVal1 < 0 Then
           MessageBox.Show("Number must be positive")
       End If
       If Not Decimal.TryParse(txtLabor.Text, decVal2) Then
           MessageBox.Show("Enter a Numeric value please")
           Return False
       End If
       If decVal2 < 0 Then
           MessageBox.Show("Number Must be positive")
       End If
       Return True
   End Function
End Class

[CoderEX]

Have you tried implementing it into the textbox text change event?

Note: I did not look through the entire code.

[SIM-1895121]

Have you tried implementing it into the textbox text change event?

Note: I did not look through the entire code.

So i would be adding it to Parts function and the Labor function? I cant figure out correct syntax for referencing it while still keeping the currency format.
This is where the text boxes get converted.
Edit: By changing it to a procedure i can simply call it using ValidInputs() wich works, however the assignment is asking me to use it as a function.

Code

Function Labor() As Decimal
       Dim decLabor As Decimal
       decLabor = FormatCurrency(txtLabor.Text)
       Return decLabor
   End Function
   Function Tax() As Decimal
       Dim dectax As Decimal
       dectax = FormatCurrency(txtParts.Text) * 0.06
       Return dectax

   End Function

[He B TeMy]

You're not calling your ValidInputs() method anywhere, either you call them on the Button that you are proceeding with the validation or you handle both textbox's textchanged events and handle it that way.

[CoderEX]

Refer to this link to see how to use control events (specifically textbox controls):
https://youtu.be/Z4SQwEVwjJg

You will be implementing the ValidInputs() function into the event.

[SIM-1895121]

Very useful video, thank you for that. I seemed to have solved my issue, well atleast as good as its going to get. Would anyone be interested in possibly tutoring me in vb.net for this semester? I work full time and dont have time to make it to my professors office. I have like 4 large assignments left. At no point would i be asking anyone to do my homework, just provide support for when i screw up. I can compensate depending on what you want.
PM me if so

[gigajew]

Non-negative integers would imply unsigned integers

"The value of an item with an integral type is the mathematical integer that it corresponds to. Integral types may be unsigned (capable of representing only non-negative integers) or signed (capable of representing negative integers as well)." - Wikipedia

Here's an example solution (from Stackoverflow user Isak Savo) modified for decimals:

[0xDEAD10CC]

Instead of throwing exceptions you should implement a TryParse().

[Dofeus]

make a parameter for your ValidateInput method.

Code

Function ValidateInput(Byval input as Integer) As Boolean

  '' Your code here

End Function

then if you are going to use it:

Code

If ValidateInput(txtParts.Text) Then
   '' true

else
   '' false

End If

[0xDEAD10CC]

make a parameter for your ValidateInput method.

Code

Function ValidateInput(Byval input as Integer) As Boolean

 '' Your code here

End Function

then if you are going to use it:

Code

If ValidateInput(txtParts.Text) Then
  '' true

else
  '' false

End If

You define the function to take an integer yet you pass in a string... LOL.

Why not ByVal the string and ByRef an int to return a boolean and return the result in the reference param passed in the way TryParse() methods work?