TextBox Control for Visual Basic 6.0 Users

Artykuł
09/03/2015

The TextBox control in Visual Basic 6.0 is replaced by the Windows Forms TextBox control in Visual Basic 2008. The names of some properties, methods, events, and constants are different, and in some cases there are differences in behavior.

Conceptual Differences

In Visual Basic 6.0, the MaxLength property determines the number of characters that can be entered into a TextBox control. If you attempt to insert text programmatically, the text will be truncated at the length specified by the MaxLength property.

In Visual Basic 2008, the behavior of the MaxLength property no longer applies to text that is added programmatically. To duplicate the Visual Basic 6.0 behavior, you need to truncate the string yourself.

In Visual Basic 6.0, the PasswordChar property is of type String; in Visual Basic 2008 it is of type Char.

In addition, there are numerous conceptual differences that apply to all controls, including differences in data binding, font handling, drag-and-drop operations, Help support and more. For more information, see Windows Forms Concepts for Visual Basic 6.0 Users.

Code Changes for the TextBox Control

The following examples illustrate differences in coding techniques between Visual Basic 6.0 and Visual Basic 2008.

Code Changes for Searching in a TextBox Control

The following code demonstrates how to search for a string in a TextBox control and highlight it.

' Visual Basic 6.0
Private Sub Form_Load ()
    Text1.Text = "Two of the peak human experiences"
    Text1.Text = Text1.Text & " are good food and classical music."
End Sub
Private Sub Form_Click ()
    Dim Search, Where
    ' Get search string from user.
    Search = InputBox("Enter text to be found:")
    ' Find string in text.
    Where = InStr(Text1.Text, Search)
    If Where Then
        Text1.SetFocus
        Text1.SelStart = Where - 1
        Text1.SelLength = Len(Search)
    Else
        MsgBox "String not found."
    End If
End Sub

' Visual BasicPrivateSub Form1_Load(ByVal sender As System.Object, ByVal e As _
System.EventArgs) HandlesMyBase.Load
    TextBox1.Text = "Two of the peak human experiences are "
    TextBox1.Text = TextBox1.Text & "good food and classical music."EndSubPrivateSub Form1_Click(ByVal sender AsObject, ByVal e As _
System.EventArgs) HandlesMe.Click
    Dim Search AsStringDimWhereAsString    ' Get search string from user.
    Search = InputBox("Enter text to be found:")
    ' Find string in text.Where = InStr(TextBox1.Text, Search)
    IfWhereThen
        TextBox1.Focus()
        TextBox1.SelectionStart = Where - 1
        TextBox1.SelectionLength = Len(Search)
    Else
        MsgBox("String not found.")
    EndIfEndSub

Code Changes for Limiting the Number of Characters in a TextBox Control

The following code demonstrates how to use the MaxLength property to specify a maximum number of characters.

' Visual Basic 6.0
Private Sub Form_Load()
    Text1.MaxLength = 5
End Sub
Private Sub SetText()
    ' Only the first five characters will be displayed.
    Text1.Text = "Hello World"
End Sub

' Visual BasicPrivateSub Form1_Load2(ByVal sender As System.Object, ByVal e As _
System.EventArgs) HandlesMyBase.Load
    TextBox1.MaxLength = 5
EndSubPrivateSub SetText()
    ' Truncate the string to equal MaxLength.
    TextBox1.Text = Strings.Left("Hello World", TextBox1.MaxLength)
EndSub

TextBox Control Property, Method, and Event Equivalencies

The following tables list Visual Basic 6.0 properties, methods, and events, along with their Visual Basic 2008 equivalents. Those properties, methods, and events that have the same name and behavior are not listed. All Visual Basic 2008 enumerations map to the System.Windows.Forms namespace unless otherwise noted.

This table provides links to topics explaining behavior differences. Where there is no direct equivalent in Visual Basic 2008, links are provided to topics that present alternatives.

Properties

Visual Basic 6.0	Visual Basic 2008 Equivalent
Alignment	TextAlign
Appearance	New implementation. For more information, see Appearance and BorderStyle Properties for Visual Basic 6.0 Users.
BackColor	BackColor Note: Colors are handled differently in Visual Basic 2008. For more information, see Color Handling for Visual Basic 6.0 Users.
Container	Parent
DataChanged DataField DataFormat DataMember DataSource	New implementation. For more information, see Data Access for Visual Basic 6.0 Users.
DragIcon DragMode	New implementation. For more information, see Drag and Drop for Visual Basic 6.0 Users.
Font FontBold FontItalic FontName FontSize FontStrikethrough FontUnderline	Font Note: Fonts are handled differently in Visual Basic 2008. For more information, see Font Object for Visual Basic 6.0 Users.
ForeColor	ForeColor Note: Colors are handled differently in Visual Basic 2008. For more information, see Color Handling for Visual Basic 6.0 Users.
Height	Height, Size Note: Coordinates are handled differently in Visual Basic 2008. For more information, see Coordinate System for Visual Basic 6.0 Users.
HelpContextID	New implementation. For more information, see Help Support for Visual Basic 6.0 Users.
HWnd	Handle
Index	New implementation. For more information, see Control Arrays for Visual Basic 6.0 Users.
Left	Left Note: Coordinates are handled differently in Visual Basic 2008. For more information, see Coordinate System for Visual Basic 6.0 Users.
LinkItem LinkMode LinkTimeOut LinkTopic	New implementation. For more information, see Dynamic Data Exchange for Visual Basic 6.0 Users.
Locked	ReadOnly
MouseIcon	New implementation. For more information, see Cannot set a custom MousePointer.
MousePointer	Cursor For a list of constants, see MousePointer for Visual Basic 6.0 Users.
OLEDragMode OLEDropMode	New implementation. For more information, see Drag and Drop for Visual Basic 6.0 Users.
Parent	FindForm method.
SelLength	SelectionLength
SelStart	SelectionStart
SelText	SelectedText
ToolTipText	ToolTip component. For more information, see ToolTip Support for Visual Basic 6.0 Users.
Top	Top Note: Coordinates are handled differently in Visual Basic 2008. For more information, see Coordinate System for Visual Basic 6.0 Users.
WhatsThisHelpID	New implementation. For more information, see Help Support for Visual Basic 6.0 Users.
Width	Width, Size Note: Coordinates are handled differently in Visual Basic 2008. For more information, see Coordinate System for Visual Basic 6.0 Users.

Methods

Visual Basic 6.0	Visual Basic 2008 Equivalent
Drag	New implementation. For more information, see Drag and Drop for Visual Basic 6.0 Users.
LinkExecute LinkPoke LinkRequest LinkSend	New implementation. For more information, see Dynamic Data Exchange for Visual Basic 6.0 Users.
Move	SetBounds Note: Coordinates are handled differently in Visual Basic 2008. For more information, see Coordinate System for Visual Basic 6.0 Users.
OLEDrag	New implementation. For more information, see Drag and Drop for Visual Basic 6.0 Users.
SetFocus	Focus
ShowWhatsThis	New implementation. For more information, see Help Support for Visual Basic 6.0 Users.
ZOrder	BringToFront or SendToBack function

Events

Visual Basic 6.0	Visual Basic 2008 Equivalent
Change	TextChanged
DblClick	DoubleClick
DragDrop DragOver	New implementation. For more information, see Drag and Drop for Visual Basic 6.0 Users.
GotFocus	Enter
LinkClose LinkError LinkNotify LinkOpen	New implementation. For more information, see Dynamic Data Exchange for Visual Basic 6.0 Users.
LostFocus	Leave
OLECompleteDrag OLEDragDrop OLEDragOver OLEGiveFeedback OLESetData OLEStartDrag	New implementation. For more information, see Drag and Drop for Visual Basic 6.0 Users.
Validate	Validating

Upgrade Notes

When a Visual Basic 6.0 application is upgraded to Visual Basic 2008, any TextBox controls are upgraded to Windows Forms TextBox controls, and properties, methods and events are upgraded to their equivalents. Where there may be differences in behavior, upgrade comments are inserted into the code.

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