[2005] Try/Catch Code correctness, advice(seeking).

[smilbuta]

Hello community.

I am handling a nothing value for a set of variables and i want to know what is the best way to do this code wise. This is not an error question but more of how i can improve consiceness of the code.

App info: the combo boxes (usename and status) are databound to tables in sql database. Im dealing with an error if a user trys to type in the feild and submit. since the user enterd data has a selected value of Nothing according to VS , i can throw an error informing the user of his stup.. AHEM!.. issue.

Currently my code looks like the following.

        Try
            If cboUserName.SelectedValue Is Nothing Then
                MessageBox.Show("woops, invalid name")
            Else
                userIdValG = CStr(cboUserName.SelectedValue)
            End If

            If cboStatus.SelectedValue Is Nothing Then
                MessageBox.Show("woops, invalid status.")
            Else
                statusIdValG = CStr(cboStatus.SelectedValue)
            End If

        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try

The core of my question deals with my IF statments and is ther a more efficient way to make that code more consice. In the actual app i have 7 combo boxes and the over all code would be slightly long and seemingly bloated... any advice welcome.. Thanx!!!

[18experience]

Set LimitToList = True for all your comboboxes in the designer, then the user won't be able to type things in that aren't in the list.

[18experience]

Sorry, I use some third party controls with enhanced properties. However, stopping the user from typing something that does not exist in the list would be the ideal solution.

[Aspnot]

There really isn't much that I would change. Since you say you go through this type of thing 7 times, I would probably make a function that handles everything for you.

userIdValG = CheckForNothing(cboUserName, "woops, invalid name")
statusIdValG = CheckForNothing(cboStatus, "woops, invalid status.")

Private Function CheckForNothing(ByVal inComboBox as ComboBox, ByVal inErrorMessage As String) As String

    Dim RetVal as String = String.Empty

    If inComboBox.SelectedValue Is Nothing Then
        MessageBox.Show(inErrorMessage)
    Else
        RetVal = cboStatus.SelectedValue.ToString()
    End If

    Return RetVal
End Function

Why not change the DropDownStyle property of the ComboBox to DropDownList. That way the user cannot type into the field. They have to select a value from the list.

[Abrium]

You don't need to use a try catch. Use a validating event, inside that event you can stipulate what can be put in and what can not and before focus from that control has completely changed the user will get a message box or some other form of notification that you deem telling them they did something wrong.

[smilbuta]

Ohh i like the function method.. seems i can use its fuction elsewhere in my code!!

THanx all..

[Abrium]

no problem