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VB.Net 前后端分离怎么实现的
1.一般来说，要实现前后端分离，前端就需要开启一个本地的服务器来运行自己的前端代码，以此来模拟真实的线上环境，并且，也是为了更好的开发。因为你在实际开发中，你不可能要求每一个前端都去搭建一个java(php)环境，并且在java环境下开发，这对于前端来说，学习成本太高了。
?2.但如果本地没有开启服务器的话，不仅无法模拟线上的环境，而且还面临到了跨域的问题，因为你如果写静态的html页面，直接在文件目录下打开的话，你是无法发出ajax请求的(浏览器跨域的限制),因此，你需要在本地运行一个服务器，可是又不想搭建陌生而庞大的java环境，怎么办法呢？nodejs正好解决了这个问题。在我们项目中，我们利用nodejs的express框架来开启一个本地的服务器，然后利用nodejs的一个http-proxy-middleware插件将客户端发往nodejs的请求转发给真正的服务器，让nodejs作为一个中间层。这样，前端就可以无忧无虑的开发了
?3.由于前后端分离后，前端和后台同时开发时，就可能遇到前端已经开发好一个页面了，可是却等待后台API接口的情况。比如说A是负责前端，B是负责后台，A可能用了一周做好了基本的结构，并且需要API接口联调后，才能继续开发，
?4.而此时B却还没有实现好所需要的接口，这种情况，怎么办呢？在我们这个项目里，我们是通过了mock来提供一些假数据，我们先规定好了API接口，设计出了一套API文档，然后我们就可以通过API文档，利用mock来返回一些假数据，这样就可以模拟发送API到接受响应的整一个过程，
?5.因此前端也不需要依赖于后端开发了，可以独立开发，等到后台的API全部设计完之后，就可以比较快速的联调。
VB.NET中怎么给TreeView的父节点添加相对应的子节点？求助各位！
Public Class Form1
Dim node(5) As TreeNode
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
Dim root As TreeNode
With TreeView1
.Nodes.Clear()
.ShowLines = True
.ShowPlusMinus = True
.ShowRootLines = True
root = .Nodes.Add("仓库") '增加根节点
.SelectedNode = root '在此根节点下添加子节点
For i = 1 To 6
node(i - 1) = .SelectedNode.Nodes.Add(i.ToString "号仓库")
Next
.ExpandAll()
End With
End Sub
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
If Val(TextBox1.Text) = 100 And Val(TextBox1.Text) = 699 Then
node(Val(TextBox1.Text) \ 100 - 1).Nodes.Add(TextBox1.Text)
End If
End Sub
Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
If Val(TextBox2.Text) = 1000000 And Val(TextBox2.Text) = 6999999 Then
For Each child As TreeNode In node(Val(TextBox2.Text) \ 1000000 - 1).Nodes
If child.Text = TextBox2.Text.Substring(1, 3) Then
child.Nodes.Add(TextBox2.Text)
Exit For
End If
Next
End If
End Sub
End Class
vb.net 磁盘文件列表，界面如图，在.net下如何实现？
预先准备三个图标文件，用于树型控件中显示磁盘符号和文件夹的图像之用。
1、窗体上添加控件如下：
组合框控件 ComboBox1，树型控件 TreeView1，列表框控件 ListBox1，图像列表控件 ImageList1。
选中TreeView1，设置其ImageList属性为ImageList1。
2、设置属性
选中图像列表控件 ImageList1，在属性窗口里，选中属性Images，单击三个小点按钮，出现图像集合编辑器窗口，单击[添加按钮]，一一把准备好的图标文件进行添加，注意先后次序，如果不符合要求可以通过上下移动按钮重新改变次序。完成后单击[确定]。
运行图如下：
完整代码如下：
Imports System.IO
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'添加系统所有磁盘目录符号
For Each MyDrive As String In Environment.GetLogicalDrives()
ComboBox1.Items.Add(MyDrive)
Next
'显示第一个磁盘符号
ComboBox1.Text = ComboBox1.Items(0)
End Sub
'递归过程添加目录树
Public Sub AddDirectory(ByVal strFatherPath As String, ByVal strPath As String, ByVal nodeFather As TreeNode)
Dim i As Integer
Dim Mynode As New TreeNode
'先添加本目录
Mynode.Text = Strings.Replace(strPath, strFatherPath "\", "", , 1)
'为节点指定未被选中时显示的图标
Mynode.ImageIndex = 1
'为节点指定被选中时显示的图标
Mynode.SelectedImageIndex = 2
nodeFather.Nodes.Add(Mynode)
Application.DoEvents()
Try
Dim str() As String = Directory.GetDirectories(strPath)
'递归遍历该目录的子文件夹
For i = 0 To str.GetUpperBound(0)
AddDirectory(strPath, str(i), Mynode)
Next
Catch ex As Exception
Debug.WriteLine(ex.Message)
End Try
Mynode = Nothing
End Sub
'根据给出的盘符添加目录树
Private Sub AddRootDirectory(ByVal DiscSymbol As String)
Dim Nynode As New TreeNode
'先把磁盘盘符添加到树中
TreeView1.Nodes.Clear()
Nynode.ImageIndex = 0
Nynode.Text = DiscSymbol
Nynode.SelectedImageIndex = -1
TreeView1.Nodes.Add(Nynode)
Dim i As Integer
'获取磁盘根目录下的文件夹
Dim str() As String = Directory.GetDirectories(DiscSymbol "\")
For i = 0 To str.GetUpperBound(0)
'调用递归过程遍历该文件夹里的所有子文件夹，并添加到树型控件
AddDirectory(DiscSymbol, str(i), Nynode)
Next
Nynode = Nothing
End Sub
Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
'根据磁盘符号的变更，显示根目录里的文件
ListBox1.Items.Clear()
For Each MyFile As String In System.IO.Directory.GetFiles(ComboBox1.Text)
ListBox1.Items.Add(MyFile)
Next
'根据磁盘符号的变更，重新显示目录树
Dim DiscSymbol As String
DiscSymbol = Microsoft.VisualBasic.Left(ComboBox1.Text, Len(ComboBox1.Text) - 1)
Call AddRootDirectory(DiscSymbol)
End Sub
'递归过程根据子目录寻找上级目录名--从而构成完整的目录路径
Private Sub AllPath(ByVal ThisNode As TreeNode, ByRef MyPathName As String)
If ThisNode.Level 1 Then
'该节点层数大于1，其父节点不是磁盘根目录
MyPathName = ThisNode.Parent.Text "\" MyPathName
Dim MyNode As TreeNode = ThisNode.Parent
Call AllPath(MyNode, MyPathName)
Else
'该节点层数等于1，其父节点就是磁盘根目录
MyPathName = ComboBox1.Text MyPathName
End If
End Sub
Private Sub TreeView1_AfterSelect(ByVal sender As System.Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles TreeView1.AfterSelect
'为了搜索选中的节点对应目录的文件，需要组成全路径
Dim MyAllPathName As String = TreeView1.SelectedNode.Text
Dim MyNode As TreeNode = TreeView1.SelectedNode
If TreeView1.SelectedNode.Level = 0 Then
'如果选中的是根节点
MyAllPathName = ComboBox1.Text
Else
'如果选中的是非根节点，调用递归过程组成全路径
Call AllPath(MyNode, MyAllPathName)
MyAllPathName = MyAllPathName "\"
End If
'根据路径，搜索文件名并显示
ListBox1.Items.Clear()
For Each MyFile As String In System.IO.Directory.GetFiles(MyAllPathName)
ListBox1.Items.Add(MyFile)
Next
End Sub
End Class
vb.net如何操作xml的element和node?
Public Function WriteConfigInfo(ByVal aSection As String, ByVal aKey As String, _
ByVal aValue As String, ByVal aFileName As String) As Boolean
If aSection = "" Then Return False
If aFileName = "" Then Return (False)
' create in instance of the class and write the config file info
Dim XmlFile As New clsXMLCfgFile(aFileName)
Return XmlFile.WriteConfigInfo(aSection, aKey, aValue)
End Function
Public Class clsXMLCfgFile
Dim Doc As New XmlDocument()
Dim FileName As String
Dim doesExist As Boolean
Public Sub New(ByVal aFileName As String)
FileName = aFileName
Try
Doc.Load(aFileName)
doesExist = True
Catch ex As Exception
If Err.Number = 53 Then
Doc.LoadXml(("configuration" "/configuration"))
Doc.Save(aFileName)
End If
End Try
End Sub
Public Function GetConfigInfo(ByVal aSection As String, ByVal aKey As String, ByVal aDefaultValue As String) As Collection
' return immediately if the file didn't exist
If doesExist = False Then
Return New Collection()
End If
If aSection = "" Then
' if aSection = "" then get all section names
Return getchildren("")
ElseIf aKey = "" Then
' if aKey = "" then get all keynames for the section
Return getchildren(aSection)
Else
Dim col As New Collection()
col.Add(getKeyValue(aSection, aKey, aDefaultValue))
Return col
End If
End Function
Public Function WriteConfigInfo(ByVal aSection As String, ByVal aKey As String, ByVal aValue As String) As Boolean
Dim node1 As XmlNode
Dim node2 As XmlNode
If aKey = "" Then
' find the section, remove all its keys and remove the section
node1 = (Doc.DocumentElement).SelectSingleNode("/configuration/" aSection)
' if no such section, return True
If node1 Is Nothing Then Return True
' remove all its children
node1.RemoveAll()
' select its parent ("configuration")
node2 = (Doc.DocumentElement).SelectSingleNode("configuration")
' remove the section
node2.RemoveChild(node1)
ElseIf aValue = "" Then
' find the section of this key
node1 = (Doc.DocumentElement).SelectSingleNode("/configuration/" aSection)
' return if the section doesn't exist
If node1 Is Nothing Then Return True
' find the key
node2 = (Doc.DocumentElement).SelectSingleNode("/configuration/" aSection "/" aKey)
' return true if the key doesn't exist
If node2 Is Nothing Then Return True
' remove the key
If node1.RemoveChild(node2) Is Nothing Then Return False
Else
' Both the Key and the Value are filled
' Find the key
node1 = (Doc.DocumentElement).SelectSingleNode("/configuration/" aSection "/" aKey)
If node1 Is Nothing Then
' The key doesn't exist: find the section
node2 = (Doc.DocumentElement).SelectSingleNode("/configuration/" aSection)
If node2 Is Nothing Then
' Create the section first
Dim e As Xml.XmlElement = Doc.CreateElement(aSection)
' Add the new node at the end of the children of ("configuration")
node2 = Doc.DocumentElement.AppendChild(e)
' return false if failure
If node2 Is Nothing Then Return False
' now create key and value
e = Doc.CreateElement(aKey)
e.InnerText = aValue
' Return False if failure
If (node2.AppendChild(e)) Is Nothing Then Return False
Else
' Create the key and put the value
Dim e As Xml.XmlElement = Doc.CreateElement(aKey)
e.InnerText = aValue
node2.AppendChild(e)
End If
Else
' Key exists: set its Value
node1.InnerText = aValue
End If
End If
' Save the document
Doc.Save(FileName)
Return True
End Function
Private Function getKeyValue(ByVal aSection As String, ByVal aKey As String, ByVal aDefaultValue As String) As String
Dim node As XmlNode
node = (Doc.DocumentElement).SelectSingleNode("/configuration/" aSection "/" aKey)
If node Is Nothing Then Return aDefaultValue
Return node.InnerText
End Function
Private Function getchildren(ByVal aNodeName As String) As Collection
Dim col As New Collection()
Dim node As XmlNode
Try
' Select the root if the Node is empty
If aNodeName = "" Then
node = Doc.DocumentElement
Else
' Select the node given
node = Doc.DocumentElement.SelectSingleNode(aNodeName)
End If
Catch
End Try
' exit with an empty collection if nothing here
If node Is Nothing Then Return col
' exit with an empty colection if the node has no children
If node.HasChildNodes = False Then Return col
' get the nodelist of all children
Dim nodeList As XmlNodeList = node.ChildNodes
Dim i As Integer
' transform the Nodelist into an ordinary collection
For i = 0 To nodeList.Count - 1
col.Add(nodeList.Item(i).Name)
Next
Return col
End Function
End Class
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把它放模块中，稍微调试一下：）就OK了
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