Modified TextBox for forms generating SQL statements

Question

An overview of what I've done:

I've inherited System.Windows.Forms.TextBox and added a few properties to help me out in creating forms that generate SQL statements.

I use to create a large function that would check for changes in the TextBox compared to a string. Then it would take text and concatenate it to a SQL statement. Now it's simple and easier to use.

I've added four properties:

• A String property to hold the default string that the textbox is initially set to and will reset back if the text is left empty.
• A String property to hold the text's associated SQL statement.
• A Boolean to check if the text has changed from the default.
• Finally, an Integer to hold an ID if there is a reason to need one, such as saving and loading text from a file by the ID.

I have not fully implemented the new textbox in my code, but I am working on it.

It may only be slightly modified, but it should cut down my code from 500+ lines of code down to less than +-30 if ran in a for-loop.

SQLTextBox.vb

Public Class ModifiedTextBox
    Inherits System.Windows.Forms.TextBox

    Private _strDefaultText As String
    Private _strSqlText As String
    Private _nID As Integer
    Private _bModified As Boolean = False

    Property ID()
        Set(nID)
            _nID = nID
        End Set
        Get
            Return _nID
        End Get
    End Property

    Property TextModified()
        Set(bModified)
            _bModified = bModified
        End Set
        Get
            Return _bModified
        End Get
    End Property

    Property SqlText()
        Set(strSqlText)
            _strSqlText = strSqlText
        End Set
        Get
            Return _strSqlText
        End Get
    End Property

    Property DefaultText()
        Set(strDefaultText)
            _strDefaultText = strDefaultText
            Me.Text = _strDefaultText
        End Set
        Get
            Return _strDefaultText
        End Get
    End Property

End Class

I've pulled an excerpt from my code. It's not much, but here is the new textbox vs the old one.

In the SQL text, I have something like ""Material Type"" in('INSERTTEXT'). SQLTextBox.Modified gets set when the user leaves the textbox (set to false b default).

'This should run every new textbox (untested)
For i As Integer = 0 To Me._icControls.txtMain.Length - 1
    If Me._icControls.txtMain(i).Modified = True Then
        sqlWhere += " AND " + Me._icControls.txtMain(i).SqlText
        Replace(sqlWhere, "INSERTTEXT", Me._icControls.txtMain(i).Text)
    End If
Next

'Old, long way around where I had split up
'the textboxes into 7 groups they belonged too.
If Me._icControls.txtMaterial(0).Text.ToString() <> DefaultStrings.Material(0) Then
    sqlWhere += " AND ""Material Type"" in('" + Me._icControls.txtMaterial(0).Text.ToString() + "')"
End If

If Me._icControls.txtMaterial(4).Text.ToString() <> DefaultStrings.Material(4) Then
    sqlWhere += " AND ""Grade"" in('" + Me._icControls.txtMaterial(4).Text.ToString() + "')"
End If

If Me._icControls.txtMaterial(5).Text.ToString() <> DefaultStrings.Material(5) Then
    sqlWhere += " AND ""PIW"" in('" + Me._icControls.txtMaterial(5).Text.ToString() + "')"
End If

I went from 200 lines of code to 6, with a minor change. That does not include the lines spent setting up the default text.

Let me know what you think of this. I'm not sure if it's really anything someone could use, but it's been very useful to me.

Answer 1

There's not much to review here really. I'd be more interested in reviewing the code that's actually doing the work, but here goes.

1. Lose the Systems Hungarian notation. The IDE/Code tells me what the data type is. That is if you...

2. Declare the data types of the properties

3. Use auto properties. There's way too much code here for how simple this is.

---

Public Class ModifiedTextBox
    Inherits System.Windows.Forms.TextBox

    Property ID() As Integer
    Property TextModified() As Boolean
    Property SqlText() As String

    Property DefaultText() As String
        Set(strDefaultText)
            _strDefaultText = strDefaultText
            Me.Text = _strDefaultText
        End Set
        Get
            Return _strDefaultText
        End Get
    End Property

End Class

Answer 2

• You don't need to prefix your variables with b\n\str.

• I would get the business logic out of the UI and into business classes

It's hard to know exactly what you are doing but this might help. I would have a SqlBuilder class and a SqlPart for each section of the where clause.

Class SqlBuilder

    Private _gradePart As New SqlPart("Grade IN ('{0}')")
    Private _piwPart As New SqlPart("PIW IN ('{0}')")

    Public ReadOnly Property GradePart As SqlPart
        Get
            Return _gradePart
        End Get
    End Property

    Public ReadOnly Property PiwPart As SqlPart
        Get
            Return _piwPart
        End Get
    End Property

    Public Function GetSqlWhere() As String

        Dim sqlWhere As String = ""

        sqlWhere &= " AND " & _gradePart.GetSqlPart()
        sqlWhere &= " AND " & _piwPart.GetSqlPart()

        Return sqlWhere
    End Function

End Class

Class SqlPart

    Public Property ID As Integer
    Public Property SqlText As String

    Private _defaultText As String
    Private _sqlValue As String
    Private _modified As Boolean = False

    Public ReadOnly Property DefaultText As String
        Get
            Return _defaultText
        End Get
    End Property

    Public ReadOnly Property Modified As Boolean
        Get
            Return _modified
        End Get
    End Property

    Public Property SqlValue As String
        Get
            Return _sqlValue
        End Get
        Set(value As String)
            If String.IsNullOrEmpty(value) Then
                value = _defaultText
            End If

            If value <> _sqlValue Then
                _sqlValue = value
                _modified = True
            End If
        End Set
    End Property

    Public Sub New(ByVal defaultText As String)

        _defaultText = defaultText

    End Sub

    Public Function GetSqlPart() As String

        Return String.Format(SqlText, _sqlValue)
    End Function

End Class

Your form just need an instance of SqlBuilder and then you just need to bind each "Part" to it's proper TextBox. All of your sql building logic would be inside these classes.