vb.net 怎么判断一个文件夹或是文本文件的存在?如果没有则创建……求代码!不要VB6.0的
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参考技术A 判断和创建可以放在一起。创建空文件夹：
Directory.CreateDirectory(文件夹完整路径)
'系统会自动判断文件夹是否存在，不存在就创建判断并创建空文件：
Using fs As New FileStream("f.txt", FileMode.OpenOrCreate)
'你可以用这个FileStream做其它事情
End Using
将变量保存到 vb.net 中的文本文件
【中文标题】将变量保存到 vb.net 中的文本文件【英文标题】：save variables to text file in vb.net 【发布时间】：2014-04-24 19:41:07 【问题描述】：正如标题所说，我想将变量保存在 .txt 文件或类似文件中。 （不是 XML）我已经尝试过 My.Settings，我想要一个更便携的解决方案。
格式如下：
[config]<br>
StartPath=C:\Users<br>
FormColour=Black
【问题讨论】：
您只是想手动完成还是想要真正的 Ini-File 处理？ 我相信你不会在 vb.net 中使用 而是使用 Chrw(10) 贾斯汀：我使用 换行，这里的格式令人困惑：/ 詹斯：我在想.ini @DivideByZero - 请为有用的答案投票并标记最佳答案以提高 *** 内容的质量。 【参考方案1】：从您的问题看来，您正在考虑类似旧 Windows 版本中的 .ini 文件的配置（或类似）文件。这样的文件有一个或多个[sections]，每个name=value 对。如果这是你的情况，请看这里：
Reading/writing an INI file
如果您要存储比示例中显示的简单平面结构更适合多级结构的数据，并且您不喜欢 XML 用于此目的，您可以考虑例如JSON（可在natively .NET 自 3.5 版起）或YAML。他们的库可免费用于 .NET。
【讨论】：
【参考方案2】：对于便携式解决方案，您可以使用我的INI File Manager，它使用起来非常简单且安全。
#Region " INI File Manager " ' By Elektro
Public Class INIFileManager
#Region " Members "
#Region " Properties "
''' <summary>
''' Indicates the initialization file path.
''' </summary>
Public Shared Property FilePath As String =
IO.Path.Combine(Application.StartupPath, Process.GetCurrentProcess().ProcessName & ".ini")
#End Region
#Region " Variables "
''' <summary>
''' Stores the initialization file content.
''' </summary>
Private Shared Content As New List(Of String)
''' <summary>
''' Stores the INI section names.
''' </summary>
Private Shared SectionNames As String() = String.Empty
''' <summary>
''' Indicates the start element index of a section name.
''' </summary>
Private Shared SectionStartIndex As Integer = -1
''' <summary>
''' Indicates the end element index of a section name.
''' </summary>
Private Shared SectionEndIndex As Integer = -1
''' <summary>
''' Stores a single sorted section block with their keys and values.
''' </summary>
Private Shared SortedSection As New List(Of String)
''' <summary>
''' Stores all the sorted section blocks with their keys and values.
''' </summary>
Private Shared SortedSections As New List(Of String)
''' <summary>
''' Indicates the INI element index that contains the Key and value.
''' </summary>
Private Shared KeyIndex As Integer = -1
''' <summary>
''' Indicates the culture to compare the strings.
''' </summary>
Private Shared ReadOnly CompareMode As StringComparison = StringComparison.InvariantCultureIgnoreCase
#End Region
#Region " Exceptions "
''' <summary>
''' Exception is thrown when a section name parameter has invalid format.
''' </summary>
Private Class SectionNameInvalidFormatException
Inherits Exception
Public Sub New()
MyBase.New("Section name parameter has invalid format." &
Environment.NewLine &
"The rigth syntax is: [SectionName]")
End Sub
Public Sub New(message As String)
MyBase.New(message)
End Sub
Public Sub New(message As String, inner As Exception)
MyBase.New(message, inner)
End Sub
End Class
#End Region
#End Region
#Region " Methods "
<System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never)>
Private Shadows Sub ReferenceEquals()
End Sub
<System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never)>
Private Shadows Sub Equals()
End Sub
Public Class [File]
<System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never)>
Private Shadows Sub ReferenceEquals()
End Sub
<System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never)>
Private Shadows Sub Equals()
End Sub
''' <summary>
''' Checks whether the initialization file exist.
''' </summary>
''' <returns>True if initialization file exist, otherwise False.</returns>
Public Shared Function Exist() As Boolean
Return IO.File.Exists(FilePath)
End Function
''' <summary>
''' Creates the initialization file.
''' If the file already exist it would be replaced.
''' </summary>
''' <param name="Encoding">The Text encoding to write the initialization file.</param>
''' <returns>True if the operation success, otherwise False.</returns>
Public Shared Function Create(Optional ByVal Encoding As System.Text.Encoding = Nothing) As Boolean
Try
IO.File.WriteAllText(FilePath,
String.Empty,
If(Encoding Is Nothing, System.Text.Encoding.Default, Encoding))
Catch ex As Exception
Throw
Return False
End Try
Return True
End Function
''' <summary>
''' Deletes the initialization file.
''' </summary>
''' <returns>True if the operation success, otherwise False.</returns>
Public Shared Function Delete() As Boolean
If Not [File].Exist Then Return False
Try
IO.File.Delete(FilePath)
Catch ex As Exception
Throw
Return False
End Try
Content = Nothing
Return True
End Function
''' <summary>
''' Returns the initialization file content.
''' </summary>
''' <param name="Encoding">The Text encoding to read the initialization file.</param>
Public Shared Function [Get](Optional ByVal Encoding As System.Text.Encoding = Nothing) As List(Of String)
Content = IO.File.ReadAllLines(FilePath,
If(Encoding Is Nothing, System.Text.Encoding.Default, Encoding)).ToList()
Return Content
End Function
''' <summary>
''' Sort the initialization file content by the Key names.
''' If the initialization file contains sections then the sections are sorted by their names also.
''' </summary>
''' <param name="RemoveEmptyLines">Remove empty lines.</param>
''' <param name="Encoding">The Text encoding to read the initialization file.</param>
''' <returns>True if the operation success, otherwise False.</returns>
Public Shared Function Sort(Optional ByVal RemoveEmptyLines As Boolean = False,
Optional ByVal Encoding As System.Text.Encoding = Nothing) As Boolean
If Not [File].Exist() Then Return False
[File].[Get](Encoding)
Select Case Section.Has(Encoding)
Case True ' initialization file contains at least one Section.
SortedSection.Clear()
SortedSections.Clear()
Section.GetNames(Encoding) ' Get the (sorted) section names
For Each name As String In SectionNames
SortedSection = Section.[Get](name, Encoding) ' Get the single section lines.
If RemoveEmptyLines Then ' Remove empty lines.
SortedSection = SortedSection.Where(Function(line) _
Not String.IsNullOrEmpty(line) AndAlso
Not String.IsNullOrWhiteSpace(line)).ToList
End If
SortedSection.Sort() ' Sort the single section keys.
SortedSections.Add(name) ' Add the section name to the sorted sections list.
SortedSections.AddRange(SortedSection) ' Add the single section to the sorted sections list.
Next name
Content = SortedSections
Case False ' initialization file doesn't contains any Section.
Content.Sort()
If RemoveEmptyLines Then
Content = Content.Where(Function(line) _
Not String.IsNullOrEmpty(line) AndAlso
Not String.IsNullOrWhiteSpace(line)).ToList
End If
End Select ' Section.Has()
' Save changes.
Return [File].Write(Content, Encoding)
End Function
''' <summary>
''' Writes a new initialization file with the specified text content..
''' </summary>
''' <param name="Content">Indicates the text content to write in the initialization file.</param>
''' <param name="Encoding">The Text encoding to read the initialization file.</param>
''' <returns>True if the operation success, otherwise False.</returns>
Public Shared Function Write(ByVal Content As List(Of String),
Optional ByVal Encoding As System.Text.Encoding = Nothing) As Boolean
Try
IO.File.WriteAllLines(FilePath,
Content,
If(Encoding Is Nothing, System.Text.Encoding.Default, Encoding))
Catch ex As Exception
Throw
Return False
End Try
Return True
End Function
End Class
Public Class [Key]
<System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never)>
Private Shadows Sub ReferenceEquals()
End Sub
<System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never)>
Private Shadows Sub Equals()
End Sub
''' <summary>
''' Return a value indicating whether a key name exist or not.
''' </summary>
''' <param name="KeyName">Indicates the key name that contains the value to modify.</param>
''' <param name="SectionName">Indicates the Section name where to find the key name.</param>
''' <param name="Encoding">The Text encoding to write the initialization file.</param>
''' <returns>True if the key name exist, otherwise False.</returns>
Public Shared Function Exist(ByVal KeyName As String,
Optional ByVal SectionName As String = Nothing,
Optional ByVal Encoding As System.Text.Encoding = Nothing) As Boolean
If Not [File].Exist() Then Return False
[File].[Get](Encoding)
[Key].GetIndex(KeyName, SectionName)
Select Case SectionName Is Nothing
Case True
Return Convert.ToBoolean(Not KeyIndex)
Case Else
Return Convert.ToBoolean(Not (KeyIndex + SectionStartIndex))
End Select
End Function
''' <summary>
''' Set the value of an existing key name.
'''
''' If the initialization file doesn't exists, or else the Key doesn't exist,
''' or else the Section parameter is not specified and the key name doesn't exist;
''' then the 'key=value' is appended to the end of the initialization file.
'''
''' if the specified Section name exist but the Key name doesn't exist,
''' then the 'key=value' is appended to the end of the Section.
'''
''' </summary>
''' <param name="KeyName">Indicates the key name that contains the value to modify.</param>
''' <param name="Value">Indicates the new value.</param>
''' <param name="SectionName">Indicates the Section name where to find the key name.</param>
Public Shared Function [Set](ByVal KeyName As String,
ByVal Value As String,
Optional ByVal SectionName As String = Nothing,
Optional ByVal Encoding As System.Text.Encoding = Nothing) As Boolean
If Not [File].Exist() Then [File].Create()
[File].[Get](Encoding)
[Key].GetIndex(KeyName, SectionName)
' If KeyName is not found and indicated Section is found, then...
If KeyIndex = -1 AndAlso SectionEndIndex <> -1 Then
' If section EndIndex is the last line of file, then...
If SectionEndIndex = Content.Count Then
Content(Content.Count - 1) = Content(Content.Count - 1) &
Environment.NewLine &
String.Format("0=1", KeyName, Value)
Else ' If not section EndIndex is the last line of file, then...
Content(SectionEndIndex) = String.Format("0=1", KeyName, Value) &
Environment.NewLine &
Content(SectionEndIndex)
End If
' If KeyName is found then...
ElseIf KeyIndex <> -1 Then
Content(KeyIndex) = String.Format("0=1", KeyName, Value)
' If KeyName is not found and Section parameter is passed. then...
ElseIf KeyIndex = -1 AndAlso SectionName IsNot Nothing Then
Content.Add(SectionName)
Content.Add(String.Format("0=1", KeyName, Value))
' If KeyName is not found, then...
ElseIf KeyIndex = -1 Then
Content.Add(String.Format("0=1", KeyName, Value))
End If
' Save changes.
Return [File].Write(Content, Encoding)
End Function
''' <summary>
''' Get the value of an existing key name.
''' If the initialization file or else the Key doesn't exist then a 'Nothing' object is returned.
''' </summary>
''' <param name="KeyName">Indicates the key name to retrieve their value.</param>
''' <param name="DefaultValue">Indicates a default value to return if the key name is not found.</param>
''' <param name="SectionName">Indicates the Section name where to find the key name.</param>
Public Shared Function [Get](ByVal KeyName As String,
Optional ByVal DefaultValue As Object = Nothing,
Optional ByVal SectionName As String = Nothing,
Optional ByVal Encoding As System.Text.Encoding = Nothing) As Object
If Not [File].Exist() Then Return DefaultValue
[File].[Get](Encoding)
[Key].GetIndex(KeyName, SectionName)
Select Case KeyIndex
Case Is <> -1 ' KeyName found.
Return Content(KeyIndex).Substring(Content(KeyIndex).IndexOf("=") + 1)
Case Else ' KeyName not found.
Return DefaultValue
End Select
End Function
''' <summary>
''' Returns the initialization file line index of the key name.
''' </summary>
''' <param name="KeyName">Indicates the Key name to retrieve their value.</param>
''' <param name="SectionName">Indicates the Section name where to find the key name.</param>
Private Shared Sub GetIndex(ByVal KeyName As String,
Optional ByVal SectionName As String = Nothing,
Optional ByVal Encoding As System.Text.Encoding = Nothing)
If Content Is Nothing Then [File].Get(Encoding)
' Reset the INI index elements to negative values.
KeyIndex = -1
SectionStartIndex = -1
SectionEndIndex = -1
If SectionName IsNot Nothing AndAlso Not SectionName Like "[[]?*[]]" Then
Throw New SectionNameInvalidFormatException
Exit Sub
End If
' Locate the KeyName and set their element index.
' If the KeyName is not found then the value is set to "-1" to return an specified default value.
Select Case String.IsNullOrEmpty(SectionName)
Case True ' Any SectionName parameter is specified.
KeyIndex = Content.FindIndex(Function(line) line.StartsWith(String.Format("0=", KeyName),
StringComparison.InvariantCultureIgnoreCase))
Case False ' SectionName parameter is specified.
Select Case Section.Has(Encoding)
Case True ' INI contains at least one Section.
SectionStartIndex = Content.FindIndex(Function(line) line.Trim.Equals(SectionName.Trim, CompareMode))
If SectionStartIndex = -1 Then ' Section doesn't exist.
Exit Sub
End If
SectionEndIndex = Content.FindIndex(SectionStartIndex + 1, Function(line) line.Trim Like "[[]?*[]]")
If SectionEndIndex = -1 Then
' This fixes the value if the section is at the end of file.
SectionEndIndex = Content.Count
End If
KeyIndex = Content.FindIndex(SectionStartIndex, SectionEndIndex - SectionStartIndex,
Function(line) line.StartsWith(String.Format("0=", KeyName),
StringComparison.InvariantCultureIgnoreCase))
Case False ' INI doesn't contains Sections.
GetIndex(KeyName, , Encoding)
End Select ' Section.Has()
End Select ' String.IsNullOrEmpty(SectionName)
End Sub
''' <summary>
''' Remove an existing key name.
''' </summary>
''' <param name="KeyName">Indicates the key name to retrieve their value.</param>
''' <param name="SectionName">Indicates the Section name where to find the key name.</param>
''' <param name="Encoding">The Text encoding to read the initialization file.</param>
Public Shared Function Remove(ByVal KeyName As String,
Optional ByVal SectionName As String = Nothing,
Optional ByVal Encoding As System.Text.Encoding = Nothing) As Boolean
If Not [File].Exist() Then Return False
[File].[Get](Encoding)
[Key].GetIndex(KeyName, SectionName)
Select Case KeyIndex
Case Is <> -1 ' Key found.
' Remove the element containing the key name.
Content.RemoveAt(KeyIndex)
' Save changes.
Return [File].Write(Content, Encoding)
Case Else ' KeyName not found.
Return False
End Select
End Function
End Class
Public Class Section
<System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never)>
Private Shadows Sub ReferenceEquals()
End Sub
<System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never)>
Private Shadows Sub Equals()
End Sub
''' <summary>
''' Adds a new section at bottom of the initialization file.
''' </summary>
''' <param name="SectionName">Indicates the Section name to add.</param>
''' <param name="Encoding">The Text encoding to read the initialization file.</param>
Public Shared Function Add(Optional ByVal SectionName As String = Nothing,
Optional ByVal Encoding As System.Text.Encoding = Nothing) As Boolean
If Not [File].Exist() Then [File].Create()
If Not SectionName Like "[[]?*[]]" Then
Throw New SectionNameInvalidFormatException
Exit Function
End If
[File].[Get](Encoding)
Select Case Section.GetNames(Encoding).Where(Function(line) line.Trim.Equals(SectionName.Trim, CompareMode)).Any
Case False ' Any of the existing Section names is equal to given section name.
' Add the new section name.
Content.Add(SectionName)
' Save changes.
Return [File].Write(Content, Encoding)
Case Else ' An existing Section name is equal to given section name.
Return False
End Select
End Function
''' <summary>
''' Returns all the keys and values of an existing Section Name.
''' </summary>
''' <param name="SectionName">Indicates the section name where to retrieve their keynames and values.</param>
Public Shared Function [Get](ByVal SectionName As String,
Optional ByVal Encoding As System.Text.Encoding = Nothing) As List(Of String)
If Content Is Nothing Then [File].Get(Encoding)
SectionStartIndex = Content.FindIndex(Function(line) line.Trim.Equals(SectionName.Trim, CompareMode))
SectionEndIndex = Content.FindIndex(SectionStartIndex + 1, Function(line) line.Trim Like "[[]?*[]]")
If SectionEndIndex = -1 Then
SectionEndIndex = Content.Count ' This fixes the value if the section is at the end of file.
End If
Return Content.GetRange(SectionStartIndex, SectionEndIndex - SectionStartIndex).Skip(1).ToList
End Function
''' <summary>
''' Returns all the section names of the initialization file.
''' </summary>
Public Shared Function GetNames(Optional ByVal Encoding As System.Text.Encoding = Nothing) As String()
If Content Is Nothing Then [File].Get(Encoding)
' Get the Section names.
SectionNames = (From line In Content Where line.Trim Like "[[]?*[]]").ToArray
' Sort the Section names.
If SectionNames.Count <> 0 Then Array.Sort(SectionNames)
' Return the Section names.
Return SectionNames
End Function
''' <summary>
''' Gets a value indicating whether the initialization file contains at least one Section.
''' </summary>
''' <param name="Encoding">The Text encoding to read the initialization file.</param>
Public Shared Function Has(Optional ByVal Encoding As System.Text.Encoding = Nothing) As Boolean
If Content Is Nothing Then [File].Get(Encoding)
Return (From line In Content Where line.Trim Like "[[]?*[]]").Any()
End Function
''' <summary>
''' Removes an existing section with all of it's keys and values.
''' </summary>
''' <param name="SectionName">Indicates the Section name to remove with all of it's key/values.</param>
''' <param name="Encoding">The Text encoding to read the initialization file.</param>
Public Shared Function Remove(Optional ByVal SectionName As String = Nothing,
Optional ByVal Encoding As System.Text.Encoding = Nothing) As Boolean
If Not [File].Exist() Then Return False
If Not SectionName Like "[[]?*[]]" Then
Throw New SectionNameInvalidFormatException
Exit Function
End If
[File].[Get](Encoding)
Select Case [Section].GetNames(Encoding).Where(Function(line) line.Trim.Equals(SectionName.Trim, CompareMode)).Any
Case True ' An existing Section name is equal to given section name.
' Get the section StartIndex and EndIndex.
[Get](SectionName)
' Remove the section range index.
Content.RemoveRange(SectionStartIndex, SectionEndIndex - SectionStartIndex)
' Save changes.
Return [File].Write(Content, Encoding)
Case Else ' Any of the existing Section names is equal to given section name.
Return False
End Select
End Function
End Class
#End Region
End Class
#End Region
以下是一些用法示例：
' Set the initialization file path.
'INIFileManager.FilePath = IO.Path.Combine(Application.StartupPath, "Config.ini")
' Create the initialization file.
'INIFileManager.File.Create()
' Check that the initialization file exist.
'MsgBox(INIFileManager.File.Exist)
' Writes a new entire initialization file with the specified text content.
'INIFileManager.File.Write(New List(Of String) From "[Section Name 1]")
' Set an existing value or append it at the enf of the initialization file.
'INIFileManager.Key.Set("KeyName1", "Value1")
' Set an existing value on a specific section or append them at the enf of the initialization file.
'INIFileManager.Key.Set("KeyName2", "Value2", "[Section Name 2]")
' Gets the value of the specified Key name,
'MsgBox(INIFileManager.Key.Get("KeyName1"))
' Gets the value of the specified Key name on the specified Section.
'MsgBox(INIFileManager.Key.Get("KeyName2", , "[Section Name 2]"))
' Gets the value of the specified Key name and returns a default value if the key name is not found.
'MsgBox(INIFileManager.Key.Get("KeyName0", "I'm a default value"))
' Gets the value of the specified Key name, and assign it to a control property.
'CheckBox1.Checked = CType(INIFileManager.Key.Get("KeyName1"), Boolean)
' Checks whether a Key exists.
'MsgBox(INIFileManager.Key.Exist("KeyName1"))
' Checks whether a Key exists on a specific section.
'MsgBox(INIFileManager.Key.Exist("KeyName2", "[First Section]"))
' Remove a key name.
'INIFileManager.Key.Remove("KeyName1")
' Remove a key name on the specified Section.
'INIFileManager.Key.Remove("KeyName2", "[Section Name 2]")
' Add a new section.
'INIFileManager.Section.Add("[Section Name 3]")
' Get the contents of a specific section.
'MsgBox(String.Join(Environment.NewLine, INIFileManager.Section.Get("[Section Name 1]")))
' Remove an existing section.
'INIFileManager.Section.Remove("[Section Name 2]")
'' Checks that the initialization file contains at least one section.
'MsgBox(INIFileManager.Section.Has())
'' Sort the initialization file (And remove empty lines).
'INIFileManager.File.Sort(True)
'' Gets the initialization file section names.
'MsgBox(String.Join(", ", INIFileManager.Section.GetNames()))
'' Gets the initialization file content.
'MsgBox(String.Join(Environment.NewLine, INIFileManager.File.Get()))
'' Delete the initialization file from disk.
'INIFileManager.File.Delete()
【讨论】：
【参考方案3】：我建议使用 app.config。使用ConfigurationManager 类，您可以轻松地读/写多个部分，几乎没有代码。 INI 作为配置手段正在消失，XML 可能会保留一段时间，我会说坚持下去。我最近写了一篇文章，展示了简单的用法：
VB.NET - Reading and writing app.config @ neolisk.com为方便起见，此处包含相关部分：
Imports System.Configuration
Imports System.Reflection
Public Class AppConfig
Private _config As Configuration
Private _settings As AppSettingsSection
Public Function GetProperty(propertyName As String) As String
Return _settings.Settings.Item(propertyName).Value
End Function
Public Sub SetProperty(propertyName As String, propertyValue As String)
_settings.Settings.Item(propertyName).Value = propertyValue
End Sub
Public Sub New()
_config = ConfigurationManager.OpenExeConfiguration(
Assembly.GetEntryAssembly().Location)
_settings = _config.AppSettings
End Sub
Protected Overrides Sub Finalize()
MyBase.Finalize()
_config.Save(ConfigurationSaveMode.Modified)
End Sub
End Class
用法：
Dim _appConfig As New AppConfig
_appConfig.SetProperty(propertyName, propertyValue)
_appConfig.GetProperty(propertyName)
您需要扩展上述类以支持多个部分。
【讨论】：
以上是关于vb.net 怎么判断一个文件夹或是文本文件的存在?如果没有则创建……求代码!不要VB6.0的的主要内容，如果未能解决你的问题，请参考以下文章