关于vb.net手写板的信息

vb.net 如何获取picturebox或者panel传递过来的消息？简单来讲就是如何捕获那些鼠标事件？

VB.NET里

如果要向非托管函数传递函数地址，需要传递一个委托对象，封送拆收器会自动把它转化为非托管函数指针。

所以，

首先要根据要传递的函数——WndMessage定义对应的委托类型：

（注意vb.net里面的Integer是32位，相当于vb6的Long）

Public Delegate Function WndProceDelegate(hwnd As Integer, msg As Integer, wp As Integer, ip As Integer) As Integer

然后SetWindowLong最后一个参数的类型要改成上面定义的委托类型：

Public Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (hwnd As Integer, nIndex As Integer, dwNewLong As WndProceDelegate) As Integer

调用的时候创建委托对象：

SetWindowLong(handle,GWL_WNDPROC,New WndProceDelegate(AddressOf WndMessage))

不过这里还有一个问题，封送拆收器只保证在平台调用期间委托对象不会被回收。所以一旦SetWindowLong执行完毕，你创建的委托对象就有可能被回收掉。可以用一个非局部变量(比如字段，静态变量）来引用要传递的委托对象，这样就不会被回收。

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另外，你可以直接继承要接受相关消息的空间，重写WndProce。

Public Class MyPanel : Inherits Panel

Protected Overrides Sub WndProc(ByRef m As Message)

Select Case m.Msg

Case WT_PACKET

Case Else

MyBase.WndProc(m)

End Select

End Sub

End Class

相关问答

Q1: 用vb.net编写记事本源代码

Dim sFileName As String

Dim Search

Private Sub dateTimeMenu_Click()

Text1.Text = Now

End Sub

Private Sub deleteMenu_Click()

Text1.Text = Left(Text1.Text, Text1.SelStart) + Mid(Text1.Text, Text1.SelStart + Text1.SelLength + 1)

End Sub

Private Sub findMenu_Click()

Search = InputBox("请输入要查找的字词：")

Dim Where1 '获取需要查找的字符串变量

Text1.SetFocus '文本框获得焦点，以显示所找到的内容Search = InputBox("请输入要查找的字词：")

Where1 = InStr(Text1.Text, Search) '在文本中查找字符串

If Where1 Then

'若找到则设置选定的起始位置并使找到的字符串高亮

Text1.SelStart = Where1 - 1

Text1.SelLength = Len(Search)

' Me.Caption = Where1 '测试用

'否则给出提示

Else: MsgBox "未找到所要查找的字符串。", vbInformation, "提示"

End If

End Sub

Private Sub findNextMenu_Click()

Dim Where2

Dim StartMe As Integer '查找的起始位置变量

Text1.SetFocus '文本框获得焦点

StartMe = Text1.SelLength + Text1.SelStart + 1 '给变量赋值

Where2 = InStr(StartMe, Text1.Text, Search) '令其从上次找到的地方找起

If Where2 Then

Text1.SelStart = Where2 - 1

Text1.SelLength = Len(Search)

Else: MsgBox "未找到所要查找的字符串.", vbInformation, "提示"

End If

End Sub

Private Sub aboutMenu_Click()

MsgBox Space(2) "文本编辑器版本号1.0" Chr(13) "由西南财经大学天府学院" Chr(13) Space(5) "肖忠 开发" Chr(13) Space(2) "copyright:天府学院"

End Sub

Private Sub allMenu_Click()

Text1.SelStart = 0

Text1.SelLength = Len(Text1.Text)

End Sub

Private Sub backcolorMenu_Click() '设置背景色代码

Form1.CommonDialog1.Action = 3

Text1.BackColor = Form1.CommonDialog1.Color

End Sub

Private Sub colorMenu_Click() '改变文字颜色代码

Form1.CommonDialog1.Action = 3

Text1.ForeColor = Form1.CommonDialog1.Color

End Sub

Private Sub cutMenu_Click()

Clipboard.SetText Text1.SelText

Text1.Text = Left(Text1.Text, Text1.SelStart) + Mid(Text1.Text, Text1.SelStart + Text1.SelLength + 1)

End Sub

Private Sub exitMenu_Click()

End

End Sub

Private Sub fontMenu_Click() '字体菜单代码

Form1.CommonDialog1.Flags = 3 Or 256

Form1.CommonDialog1.Action = 4

If Len(Form1.CommonDialog1.FontName) = 0 Then

Form1.Text1.FontName = "宋体"

Else

Form1.Text1.FontName = Form1.CommonDialog1.FontName

End If

Form1.Text1.FontSize = Form1.CommonDialog1.FontSize

If Form1.CommonDialog1.FontBold = True Then

Form1.Text1.FontBold = True

Else

Form1.Text1.FontBold = False

End If

If Form1.CommonDialog1.FontItalic = True Then

Form1.Text1.FontItalic = True

Else

Form1.Text1.FontItalic = False

End If

Text1.ForeColor = Form1.CommonDialog1.Color

End Sub

Private Sub Form_Load()

Form1.Text1.Width = Form1.Width - 130

Form1.Text1.Height = Form1.Height

End Sub

Private Sub Form_Resize()

Form1.Text1.Width = Form1.Width - 130

Form1.Text1.Height = Form1.Height

End Sub

Private Sub help1Menu_Click()

Form1.CommonDialog1.HelpCommand = cdlHelpForceFile

Form1.CommonDialog1.HelpFile = "c:\windows\system32\winhelp.hlp"

CommonDialog1.ShowHelp

End Sub

Private Sub newMenu_Click()

If Len(Trim(Text1.Text)) = 0 Then

Form1.Caption = "我的记事本" "--" "未命名"

sFileName = "未命名"

Text1.FontSize = 15

Text1.FontName = "宋体"

Text1.Text = ""

Else

Call saveAsMenu_Click

Form1.Caption = "我的记事本" "--" "未命名"

sFileName = "未命名"

Text1.FontSize = 15

Text1.FontName = "宋体"

Text1.Text = ""

End If

End Sub

Private Sub openMenu_Click() '打开文件代码

If Len(Trim(Text1.Text)) = 0 Then

Form1.Caption = "我的记事本"

Form1.CommonDialog1.Filter = "文本文件|*.txt"

Form1.CommonDialog1.Flags = 4096

Form1.CommonDialog1.Action = 1

If Len(Form1.CommonDialog1.FileName) 0 Then

sFileName = Form1.CommonDialog1.FileName

Form1.Caption = Form1.Caption "--" Form1.CommonDialog1.FileTitle

Open sFileName For Input As #1

Text1.FontSize = 15

Text1.FontName = "宋体"

Do While Not EOF(1)

Line Input #1, Text$

All$ = All$ + Text$ + Chr(13) + Chr(10)

Loop

Text1.Text = All

Close #1

End If

Else

Call saveAsMenu_Click

Form1.Caption = "我的记事本"

Form1.CommonDialog1.Filter = "文本文件|*.txt"

Form1.CommonDialog1.Flags = 4096

Form1.CommonDialog1.Action = 1

If Len(Form1.CommonDialog1.FileName) 0 Then

sFileName = Form1.CommonDialog1.FileName

Form1.Caption = Form1.Caption "--" Form1.CommonDialog1.FileTitle

Open sFileName For Input As #1

Text1.FontSize = 15

Text1.FontName = "宋体"

Do While Not EOF(1)

Line Input #1, Text$

All$ = All$ + Text$ + Chr(13) + Chr(10)

Loop

Text1.Text = All

Close #1

End If

End If

End Sub

Private Sub pasteMenu_Click() '粘贴菜单代码

Text1.Text = Left(Text1.Text, Text1.SelStart) + Clipboard.GetText() + Mid(Text1.Text, Text1.SelStart + Text1.SelLength + 1)

End Sub

Private Sub printMenu_Click()

Form1.CommonDialog1.ShowPrinter

For i = 1 To CommonDialog1.Copies

Printer.Print Text1.Text

Printer.Print Text1.Text

Next

Printer.EndDoc

End Sub

Private Sub saveAsMenu_Click() '另存为菜单代码

If Len(Trim(Text1.Text)) 0 Then

Form1.CommonDialog1.DialogTitle = "保存文件"

Form1.CommonDialog1.InitDir = "D:\"

Form1.CommonDialog1.Filter = "文本文件|*.txt"

Form1.CommonDialog1.Flags = 2

Form1.CommonDialog1.ShowSave

If Len(Form1.CommonDialog1.FileName) 0 Then

sFileName = Form1.CommonDialog1.FileName

Open sFileName For Output As #1

whole$ = Text1.Text

Print #1, whole

Close #1

End If

End If

End Sub

Private Sub saveMenu_Click()

If Len(Trim(Text1.Text)) 0 Then

Form1.CommonDialog1.DialogTitle = "保存文件"

Form1.CommonDialog1.InitDir = "D:\"

Form1.CommonDialog1.FileName = "新建文本"

Form1.CommonDialog1.Filter = "文本文件|*.txt"

Form1.CommonDialog1.Flags = 2

Form1.CommonDialog1.ShowSave

If Len(Form1.CommonDialog1.FileName) 0 Then

sFileName = Form1.CommonDialog1.FileName

Open sFileName For Output As #1

whole$ = Text1.Text

Print #1, whole

Close #1

End If

End If

End Sub

Private Sub statusMenu_Click()

End Sub

Q2: 关于vb.net 和 mfc 和.NET

C#还是会有一个很快的发展期，指不定什么时候就来一个很大的更新，我又要重新板砖

于是我决定选择VB.NET---其实C#与vb.net是一样的东西。

VB.NET做C/S程序的话，应该看些什么资料？---VS的安装目录下自带了数量巨大的Samples，各种语言的都有，再结合MSDN、Codeproject、Stackoverflow、Codeplex等网站就够了。

拖控件的就不用多说了---可惜vb.net和C#都是拖控件的。

Q3: VB.NET如何显示多种颜色的一段文本？

Label控件是没有办法实现多种颜色的文字的，只能用RichTextBox来实现，而且你的自定义格式字符串也没有结尾的，这样很不好，至少也要red红色字/redyellow黄色字/yellow，而且实现也很麻烦的，下面的代码我没有检测正确性，有错误的自己改一改吧

Dim colortag() as string

dim colors() as color

const txt as string="red红色字/redyellow黄色字/yellow"

private sub Form_Load(object sender,eventargs e)handles mybase.load

colortag(0)="red":Colortag(1)="yellow"

colors(0)=color.red:colors(1)=color.yellow

richtextbox1.text=txt

for i as integer=0 to colortag.lenght-1

dim tag as string="" colortag(i) ""

dim endtag as string="/" colortag(i) ""

dim find as integer=1

do

find=instr(find,txt,tag)+tag.lenght

if(find0)then

dim find1 as integer=instr(find,txt,endtag)

richtextbox1.SelectionStart=find

richtextbox1.selectionlenght=find1-find

richtextbox1.selectioncolor=colors(i)

find=find1

else

exit do

end if

loop

next

end sub

Q4: 导师出了一个问题，如何用C++实现手写电子签名。要求是在触屏上面完成的。。。希望有人可以帮帮我，想想思

写个软画刷（毛笔样式（我原来用OPENGL做的））

把绘图结果保存成图片

然后对整个图片进行MD5操作

MD5的结果就是数字签名

触屏只是输入的问题，其实和鼠标类似的。

Q5: 请问如何用vb.net编写程序控制led电子屏显示文字？

主要是对SerialPort控件的编程和数据库的读取,

在数据库读取方面可以用 DataSet ,BindingSource , TableAdapter 等数据绑定控件,

SerialPort控件的具体读写方法建议你看MSDN,大概是:

Private Sub 关闭和启动串口()

Try

If 串口.IsOpen Then

串口.Close()

End If

串口.Open()

Catch ex As Exception

''''

End Try

End Sub

Private Sub 串口的读与写()

......

Dim 发送字节() As Byte, 返回字节 As Byte

Try

'例如要发送字节: 6D

发送字节 = BitConverter.GetBytes(CByte("H6D"))

串口.Write(发送字节, 0, 1)

......

'例如读串口返回的字节

返回字节 = 串口.ReadByte

Catch ex As Exception

''''

End Try

......

End Sub

'等等