vb.net 中new的具体用法?以及实例化是什么意思?.new
就是实例化vb.net字典用法 , 比如实例化一个类 , 你才能访问,,
好比,你是张三,把你的地址告诉了vb.net字典用法我,我在能找到你家在哪,这个过程就可以称为实例化 。
使用New关键字建立一个新的对象和用它属的类来定义是一样的 。New关键字可以被用作来建立一个窗体、类模块以及集合的实例 。用户在设计的时候建立的每一个窗体都是一个类 。New关键字能够用来建立一个类的实例 。
可以通过以下步骤来建立一个类的实例:
(1)在窗体上画一个按钮和几个其vb.net字典用法他的控件 。
(2)按钮的Click事件过程加入以下代码:
Dim
x
AS
New
Form1
x.Show
(3)运行程序,并且点击几次按钮,把最前面的窗体移开 , 因为窗体是一个有可视界面的类,此时可以看见有很多窗体的拷贝,每一个窗体具有相同的控件,并且出现在一个地方 。
(4)将列代码加到按钮的click事件过程中:
Dim
f
As
Form1
f=New
Form1
f.text="hello"
f.Show
使用New关键字可以从类模块中定义的类中建立一个新的集合和对象,要知道它们怎样工作,可以参考下面的例子:
(1)建立一个新的工程,并且在一个名为Form1的窗体上画一个按钮控件 。
(2)在Project(项目)菜单下,选择"Add
Class"给工程添加一个类
(3)把新的类命名为ShowMe.VB
(4)在该新类中加入如下代码:
PUblic
Class
ShowMe
Sub
ShowFrm()
Dim
frmNew
As
Form1
frmNew=New
Form1
frmNew.Show()
【vb.net字典用法 vba字典的使用】frmNew.WindowState=1
End
Sub
End
Class
(5)在Button1_click事件的过程中加入如下代码:Protected
Sub
Button1_Click(Byval
sender
As
System.Object,_
Byval
AS
System.EventArgs)
Dim
clsNew
As
New
ShowMe()
clsNew.ShowFrm()End
Sub
运行程序,并且点击几次按钮,将看见每创建一个ShowMe类的新的实例时,在桌面上有一个最小化的窗体的图标 。
New关键字只能用来建立一个类的对象 , 不能建立一个基于基本的数据类型的对象,例如Integer 。而且,不能建立一个基于一个具体对象的对象 。例如,下面的代码根据一个名为SomeClass的类 , 建立了一个名为Objx的对象,面后又错误地企图根据对象Objx再建立一个其他的对象:
Dim
Objx
As
New
SomeClass()
Dim
Objx
AS
New
Objx()
以上代码是非法的 。
呵呵##~
VB.NET 中的Of是什么意思泛型参数,表示一种特定类型,通常用于集合List,Dictionary之类的 。
原型:Dictionary(Of TKey, TValue)
原型不能直接使用 , 必须给TKey, TValue指定一个类型(Type)
强类型字典:Dictionary(Of String, String)
表示键和值都为String类型的字典 。
vb.net copymemory 用法Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)
参数
Destination要复制内存块的目的地址 。
Source 要复制内存块的源地址 。
Length 指定要复制内存块的大?。ノ晃纸?
返回值 该函数为VOID型,没有返回值 。
用VB语言制作英汉小辞典Public Class Form1
Inherits System.Windows.Forms.Form
Public filename As String = "英汉词典.txt"
Public myword(6500, 1) As String
Public words As Integer = 0
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim a As String
Dim b As Integer
Dim i As Integer = 0
Dim n As String
Dim m As String
Dim stringb As Integer
TextBox1.Text = ""
TextBox2.Text = ""
FileOpen(1, "英汉词典.txt", OpenMode.Input)
Do While Not EOF(1)
a = LineInput(1)
b = InStr(a, " ")
n = Microsoft.VisualBasic.Left(a, b - 1)
myword(i, 0) = n
ListBox1.Items.Add(n)
stringb = Len(a) - b
m = Trim(Microsoft.VisualBasic.Right(a, stringb))
myword(i, 1) = m
i= 1
Loop
words = i
FileClose(1)
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim i As Integer = -1
If TextBox1.Text = "" Then
MessageBox.Show("不能输入空格,请重新输入")
TextBox2.Text = ""
TextBox1.Focus()
Exit Sub
Else
For i = i1 To words
If LCase(TextBox1.Text) = LCase(myword(i, 0)) Then
TextBox2.Text = Trim(myword(i, 1))
Exit Sub
End If
Next
MessageBox.Show(" 您需要的单词不存在,请重新输入")
End If
End Sub
Private Sub ListBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListBox1.SelectedIndexChanged
Try
TextBox1.Text = myword(ListBox1.SelectedIndex, 0)
TextBox2.Text = Trim(myword(ListBox1.SelectedIndex, 1))
Catch ex As Exception
End Try
Exit Sub
End Sub
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
Dim ch, enterwords As String
Dim j, m As Integer
If -1 = ListBox1.SelectedIndex Then
MsgBox("请选择单词", , "")
ListBox1.Focus()
Exit Sub
End If
enterwords = InputBox("请修改单词", "修改单词", Trim(myword(ListBox1.SelectedIndex, 0)))
Do While enterwords = ""
m = MsgBox("单词不能为空", MsgBoxStyle.RetryCancel, "修改单词")
If m = 4 Then
enterwords = InputBox("请修改单词", "修改单词", Trim(myword(ListBox1.SelectedIndex, 0)))
Else
Exit Sub
End If
Loop
ch = InputBox("请修改中文意思", "修改单词", Trim(myword(ListBox1.SelectedIndex, 1)))
Do While ch = ""
m = MsgBox("中文意思不能为空", MsgBoxStyle.RetryCancel, "修改单词")
If m = 4 Then
ch = InputBox("请修改中文意思", "修改单词", Trim(myword(ListBox1.SelectedIndex, 1)))
Else
Exit Sub
End If
Loop
myword(ListBox1.SelectedIndex, 1) = ch
myword(ListBox1.SelectedIndex, 0) = enterwords
FileOpen(1, filename, OpenMode.Output)
For j = 0 To words - 1
PrintLine(1, myword(j, 0)" "myword(j, 1))
Next
FileClose(1)
MsgBox("修改成功")
ListBox1.Items.Clear()
Form1_Load(sender, e)
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Dim i As Integer = 0
Dim k, m As Integer
Dim enterwords, ch As String
enterwords = InputBox("请输入要添加的单词", "添加单词")
Do While enterwords = ""
m = MsgBox("单词不能为空 , 请输入单词!", MessageBoxButtons.RetryCancel, "添加单词")
If m = 4 Then
enterwords = InputBox("请输入要添加的单词", "添加单词")
Else
Exit Sub
End If
Loop
ch = InputBox("请输入中文意思", "添加中文")
Do While ch = ""
m = MsgBox("中文不能为空,请输入中文意思!", MessageBoxButtons.RetryCancel, "添加中文")
If m = 4 Then
ch = InputBox("请输入中文意思", "添加中文")
Else
Exit Sub
End If
Loop
Do While LCase(myword(i, 0))LCase(enterwords)
i = i1
If words = i Then
myword(i, 0) = enterwords
myword(i, 1) = ch
words = words1
FileOpen(1, filename, OpenMode.Output)
For i = 0 To words - 1
PrintLine(1, myword(i, 0)" "myword(i, 1))
Next
ListBox1.Items.Clear()
FileClose(1)
ListBox1.Items.Clear()
Form1_Load(sender, e)
MessageBox.Show("添加成功")
Exit Sub
End If
Loop
If LCase(myword(i, 0)) = LCase(enterwords) Then
MessageBox.Show("该单词已存在!")
ListBox1.SelectedIndex = i
Exit Sub
ElseIf LCase(myword(0, 0))LCase(enterwords) Then
For k = words To 0 Step -1
myword(k1, 0) = myword(k, 0)
myword(k1, 1) = myword(k, 1)
Next
myword(0, 0) = enterwords
myword(0, 1) = ch
words = words1
FileOpen(1, filename, OpenMode.Output)
For i = 0 To words - 1
PrintLine(1, myword(i, 0)" "myword(i, 1))
Next
ListBox1.Items.Clear()
FileClose(1)
Form1_Load(sender, e)
MessageBox.Show("添加成功")
Exit Sub
End If
For k = words To i1 Step -1
myword(k1, 0) = myword(k, 0)
myword(k1, 1) = myword(k, 1)
Next k
myword(i, 0) = enterwords
myword(i, 1) = ch
words = words1
FileOpen(1, filename, OpenMode.Output)
For i = 0 To words - 1
PrintLine(1, myword(i, 0)" "myword(i, 1))
Next
FileClose(1)
ListBox1.Items.Clear()
Form1_Load(sender, e)
MessageBox.Show("添加成功")
Exit Sub
End Sub
Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
Dim i, j, k As Integer
If -1 = ListBox1.SelectedIndex Then
MsgBox("请选择单词", , "")
ListBox1.Focus()
Exit Sub
End If
k = MsgBox("确定是否删除", MsgBoxStyle.YesNo, "提示")
If k = 6 Then
For i = ListBox1.SelectedIndex To words
myword(i, 0) = myword(i1, 0)
myword(i, 1) = myword(i1, 1)
Next
words = words - 1
FileOpen(1, filename, OpenMode.Output)
For j = 0 To words - 1
PrintLine(1, myword(j, 0)" "myword(j, 1))
Next
FileClose(1)
MsgBox("单词已删除")
ListBox1.Items.RemoveAt(ListBox1.SelectedIndex)
ListBox1.Refresh()
TextBox1.Text = ""
TextBox2.Text = ""
Exit Sub
Else
Exit Sub
End If
End Sub
Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click
TextBox1.Text = ""
TextBox2.Text = ""
End Sub
End Class
这是代码,文字性的内容自己去做 。
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