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

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.

Code:

---

        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!!!

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.

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.

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.

Code:

---

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.

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.

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

THanx all..

no problem