حركت كردن ميان كنترلهاي يك فرم در Vb.net
چگونه مي توان ميان كنترلهاي يك فرم بخصوص TextBox هاي آن حركت كرد؟ (البته با زدن كليد Enter)
دو راه حل وجود دارد:
1- در رويداد KeyDown هر كنترل دستورات زير را بنويسيد:
کد:
If e.KeyCode = Keys.Enter Then
نام كنترل بعدي.Focus()
End If
اما اين كار يك عيب بزرگ دارد وآنكه براي هركنترل بايد اين كار را انجام دهيد كه براي فرمهايي كه كنترل زياد دارند وقت گير و خسته كننده است.
2- ابتدا خاصيت KeyPreview فرم را به True تغيير دهيد سپس در رويداد KeyDown فرم دستورات زير را بنويسيد:
کد:
If e.KeyCode = Keys.Enter Then
Dim Con As Control
Con = Me.GetNextControl(Me.ActiveControl, True)
Con.Focus()
End If
توضيح :
دستور Me.ActiveControl نام كنترلي كه Focus را در اختيار دارد برمي گرداند ودستورMe.GetNextControl نام كنترل بعدي را كه Focus را در اختيار مي گيرد برمي گرداند ودر Con قرار مي دهد و دستورCon.Focus باعث مي شود تا Focus در اختيار كنترل قرار گيرد.
نكته : فراموش نكنيد براي صحيح كاركردن دستورات بالا بايد خاصيت TabIndex هركنترل به درستي تنظيم شده باشد.
برنامه ضرب اعداد بزرگ در Vb.net
کد:
Private Function Multiply(ByVal TX1 As String, ByVal TX2 As String) As String
Dim a(5), b(5), c(5) As Byte
Dim S1, S2 As String
If TX1 = "0" Or TX2 = "0" Then
Return "0"
Else
S1 = TX1
S2 = TX2
ReDim a(S1.Length - 1)
ReDim b(S2.Length - 1)
If S1.Length >= S2.Length Then
ReDim c(S1.Length * 2 - 1)
Else
ReDim c(S2.Length * 2 - 1)
End If
Dim i1 As Short = 0
For i As Short = S1.Length - 1 To 0 Step -1
a(i1) = S1.Chars(i).ToString
i1 += 1
Next
i1 = 0
For i As Short = S2.Length - 1 To 0 Step -1
b(i1) = S2.Chars(i).ToString
i1 += 1
Next
Dim k, t, t1, x As Short
For i As Short = 0 To S1.Length - 1
k = i
t = 0
t1 = 0
For j As Short = 0 To S2.Length - 1
x = a(i) * b(j) + t
c(k) += x Mod 10 + t1
If t1 <> 0 Then
t1 = 0
End If
If c(k) >= 10 Then
t1 = c(k) \ 10
c(k) = c(k) Mod 10
End If
t = x \ 10
k += 1
Next
c(k) = t + t1
Next
Dim S3 As String
Dim flag As Boolean = False
For i As Short = UBound(c) To 0 Step -1
If c(i) <> 0 Then
S3 &= c(i)
flag = True
Else
If flag = True Then
S3 &= c(i)
End If
End If
Next
Return S3
End If
End Function
یک کلاس برای ارتباط با WebCam
کد:
Public Class iCam
#Region "Api/constants"
Private Const WS_CHILD As Integer = &H40000000
Private Const WS_VISIBLE As Integer = &H10000000
Private Const SWP_NOMOVE As Short = &H2S
Private Const SWP_NOZORDER As Short = &H4S
Private Const WM_USER As Short = &H400S
Private Const WM_CAP_DRIVER_CONNECT As Integer = WM_USER + 10
Private Const WM_CAP_DRIVER_DISCONNECT As Integer = WM_USER + 11
Private Const WM_CAP_SET_VIDEOFORMAT As Integer = WM_USER + 45
Private Const WM_CAP_SET_PREVIEW As Integer = WM_USER + 50
Private Const WM_CAP_SET_PREVIEWRATE As Integer = WM_USER + 52
Private Const WM_CAP_GET_FRAME As Long = 1084
Private Const WM_CAP_COPY As Long = 1054
Private Const WM_CAP_START As Long = WM_USER
Private Const WM_CAP_STOP As Long = (WM_CAP_START + 68)
Private Const WM_CAP_SEQUENCE As Long = (WM_CAP_START + 62)
Private Const WM_CAP_SET_SEQUENCE_SETUP As Long = (WM_CAP_START + 64)
Private Const WM_CAP_FILE_SET_CAPTURE_FILEA As Long = (WM_CAP_START + 20)
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Short, ByVal lParam As String) As Integer
Private Declare Function capCreateCaptureWindowA Lib "avicap32.dll" (ByVal lpszWindowName As String, ByVal dwStyle As Integer, ByVal x As Integer, ByVal y As Integer, ByVal nWidth As Integer, ByVal nHeight As Short, ByVal hWndParent As Integer, ByVal nID As Integer) As Integer
Private Declare Function capGetDriverDescriptionA Lib "avicap32.dll" (ByVal wDriver As Short, ByVal lpszName As String, ByVal cbName As Integer, ByVal lpszVer As String, ByVal cbVer As Integer) As Boolean
Private Declare Function BitBlt Lib "GDI32.DLL" (ByVal hdcDest As IntPtr, ByVal nXDest As Integer, ByVal nYDest As Integer, ByVal nWidth As Integer, ByVal nHeight As Integer, ByVal hdcSrc As IntPtr, ByVal nXSrc As Integer, ByVal nYSrc As Integer, ByVal dwRop As Int32) As Boolean
#End Region
Private iDevice As String
Private hHwnd As Integer
Private lwndC As Integer
Public iRunning As Boolean
Private CamFrameRate As Integer = 15
Private OutputHeight As Integer = 240
Private OutputWidth As Integer = 360
Public Sub resetCam()
'resets the camera after setting change
If iRunning Then
closeCam()
Application.DoEvents()
If setCam() = False Then
MessageBox.Show("Errror Setting/Re-Setting Camera")
End If
End If
End Sub
Public Sub initCam(ByVal parentH As Integer)
'Gets the handle and initiates camera setup
If Me.iRunning = True Then
MessageBox.Show("Camera Is Already Running")
Exit Sub
Else
hHwnd = capCreateCaptureWindowA(iDevice, WS_VISIBLE Or WS_CHILD, 0, 0, OutputWidth, CShort(OutputHeight), parentH, 0)
If setCam() = False Then
MessageBox.Show("Error setting Up Camera")
End If
End If
End Sub
Public Sub setFrameRate(ByVal iRate As Long)
'sets the frame rate of the camera
CamFrameRate = CInt(1000 / iRate)
resetCam()
End Sub
Private Function setCam() As Boolean
'Sets all the camera up
If SendMessage(hHwnd, WM_CAP_DRIVER_CONNECT, CShort(iDevice), CType(0, String)) = 1 Then
SendMessage(hHwnd, WM_CAP_SET_PREVIEWRATE, CShort(CamFrameRate), CType(0, String))
SendMessage(hHwnd, WM_CAP_SET_PREVIEW, 1, CType(0, String))
Me.iRunning = True
Return True
Else
Me.iRunning = False
Return False
End If
End Function
Public Function closeCam() As Boolean
'Closes the camera
If Me.iRunning Then
closeCam = CBool(SendMessage(hHwnd, WM_CAP_DRIVER_DISCONNECT, 0, CType(0, String)))
Me.iRunning = False
End If
End Function
Public Function copyFrame(ByVal src As PictureBox, ByVal rect As RectangleF) As Bitmap
If iRunning Then
Dim srcPic As Graphics = src.CreateGraphics
Dim srcBmp As New Bitmap(src.Width, src.Height, srcPic)
Dim srcMem As Graphics = Graphics.FromImage(srcBmp)
Dim HDC1 As IntPtr = srcPic.GetHdc
Dim HDC2 As IntPtr = srcMem.GetHdc
BitBlt(HDC2, 0, 0, CInt(rect.Width), _
CInt(rect.Height), HDC1, CInt(rect.X), CInt(rect.Y), 13369376)
copyFrame = CType(srcBmp.Clone(), Bitmap)
'Clean Up
srcPic.ReleaseHdc(HDC1)
srcMem.ReleaseHdc(HDC2)
srcPic.Dispose()
srcMem.Dispose()
Else
MessageBox.Show("Camera Is Not Running!")
End If
End Function
Public Function FPS() As Integer
Return CInt(1000 / (CamFrameRate))
End Function
End Class
منبع:
کد:
http://barnamenevis.org/forum/showpost.php?p=355455&postcount=55
تشخیص لینک کلیک شده در صفحات وب
روي فرم يک کنترل وب بروزر قرار دهيد و کد هاي زير را وارد کنيد:
کد:
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
WebBrowser1.Navigate("http://www.google.com")
End Sub
Private Sub webControl_DocumentCompleted(ByVal sender As Object, ByVal e As System.Windows.Forms.WebBrowserDocumentCompletedEventArgs) Handles WebBrowser1.DocumentCompleted
Dim link As HtmlElement
Dim links As HtmlElementCollection = WebBrowser1.Document.Links
For Each link In links
link.AttachEventHandler("onclick", AddressOf LinkClicked)
Next
End Sub
Private Sub LinkClicked(ByVal sender As Object, ByVal e As EventArgs)
Dim link As HtmlElement = WebBrowser1.Document.ActiveElement
Dim url As String = link.GetAttribute("href")
MsgBox("Link Clicked: " & link.InnerText & vbCrLf & _
"Destination: " & url)
End Sub
