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Thm mt i tng trong lc chng trnh thc thi

Ngoi cc Control trong lc thit k chng trnh c bn to ra, trong lc chng trnh ang thc thi (chy) bn vn c th to thm cc Control mt cch kh d dng vi iu kin nh sau  to nn mt mng cc Control.

- Phi c ti thiu 1 Control ban u

- C thuc tnh Index = 0

Trong lc chng trnh chy bn c th dng cu lnh sau y  Load mt Control ln. Khi Control c Load ln n s mang cc thuc tnh ging ht vi ci ban u ch tr ch s Index. Bn hy dng lnh sau  Load. Vi Index l ch s ca phn t k tip trong mng

Load object(index)

Visual Basic ch cho php bn Load n 32767 (Gii hn ca Integer) phn t trong mt mng m thi.

Sau y l mt th d minh ha cch thm CommandButton

- Bn hy to mt CommandButton, t thuc tnh Name = cmdBtn v Index = 0 (zero). Khi bn nhp vo thuc tnh Index ca mt con s cng c ngha l bn  to mt mng cc i tng .

- Paste vo on Code sau:

Private Sub cmdBtn_Click(Index As Integer)

Dim btn As CommandButton

Dim iIndex As Integer

iIndex = cmdBtn.Count

If iIndex <= 32767 Then

    Load cmdBtn(iIndex)

    Set btn = cmdBtn(iIndex)

    With btn

        .Top = cmdBtn(iIndex - 1).Top + 620

        .Caption = "Command" & iIndex + 1

        .Visible = True

    End With

    Set btn = Nothing

End If

End Sub

Nhn F5 chy th chng trnh, Click chut vo CommandButton bn s thy mt CommandButton na xut hin pha di.

Nh ToolTip  hin th d liu qu di trong ListBox

Bn c khi no bn gp trng hp Item cn hin th trong ListBox li di hn b rng ca Listox khng ?

Trong rt d hm phi khng ? T nhin mt khc ui ca ngi ta.

V y l gii php. Bn hy dng mt ToolTip, ni dung ca ToolTip chnh l ni dung Item ca ListBox mi khi bn r Mouse n.

Hy m 1 form mi, trn  to 1 ListBox (Name: List1). Ti phi dng n hm API SendMessage v hng (LB_ITEMFROMPOINT = &H1A9)  lm vic ny.

Option Explicit

Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
(ByVal hwnd As Long,ByVal wMsg As Long, ByVal wParam As Long, _
lParam As Any) As Long

Private Const LB_ITEMFROMPOINT = &H1A9

 th tc tnh hung Form_Load() bn hy thm vo vi dng lnh  Add vo ListBox (Nh cho dng d liu di di mt cht  thy r tc dng).

Private Sub Form_Load()

List1.AddItem "Tao bo dia cai dat phan mem"

List1.AddItem "Su dung Font Navigator"

List1.AddItem "Tao man hinh Splash Screen"

List1.AddItem "EditPlus (Text/HTML Editor for Windows)"

List1.AddItem "Tu tao Progress bar cho ung dung"

List1.AddItem "Combo box tu hien danh sach khi nhan focus"

List1.AddItem "Cua so FormLayout dung de lam gi"

End Sub

'Khi r mouse trn ListBox, th tc sau y s ly ni dung ca Item ti v tr Mouse v cho hin ln bng ToolTip.

Private Sub List1_MouseMove(Button As Integer, Shift As Integer, _
X As Single, Y As Single)

    Dim lXPoint As Long

    Dim lYPoint As Long

    Dim lIndex As Long

If Button = 0 Then 'Nu khng c nt no c nhn

          lXPoint = CLng(X / Screen.TwipsPerPixelX)

          lYPoint = CLng(Y / Screen.TwipsPerPixelY)

          With List1              

                lIndex = SendMessage(.hwnd,LB_ITEMFROMPOINT,0, _
                ByVal ((lYPoint * 65536) + lXPoint))

'Hin ToolTip hoc xa ci trc 

If (lIndex >= 0) And (lIndex <= .ListCount) Then

                  .ToolTipText = .List(lIndex)

                Else

                  .ToolTipText = ""

                End If

          End With

    End If

End Sub

Lm sao  TextBox t ng Select vn bn mi khi nhn focus ?

Bn c ch   hu ht cc phn mm, nu ngi dng cn nhp liu vo mt hp vn bn (TextBox) no , th khi ngi dng nhn Mouse hoc Tab  chuyn n TextBox, tc th ton b d liu ang hin c trong TextBox s c Select. Cch ny gip ngi dng g d liu khc  ln d liu hin hu, m khng phi mt cng xa i ri g li ci khc.

Vit mt th tc ring, th tc ny nhn i s l mt TextBox

Public Sub FocusMe(ctlName As TextBox)

    With ctlName

        .SelStart = 0

        .SelLength = Len(ctlName)

    End With

End Sub

'By gi bn hy gi hm ny trong th tc tnh hung GotFocus ca mt TextBox

Private Sub txtFocusMe_GotFocus()

    Call FocusMe(txtFocusMe)

End Sub

Hy vng nhng cu hi nh ny s gip ch cho bn trong lc pht trin mt ng dng bng Visual Basic. Chc bn thnh cng.

chu nht, thang hai 03, 2002 05:52:34 CH
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