我正在尝试更有效的方式来生成表单。我的实验可以直接通过它们的类引用来链接字符串和其他类型,并使用它来更新原始值而不使用任何强类型代码。获取byref参考字符串的内存地址
我一直在使用GCHandle.AddrOfPinnedObject来获取字符串的内存地址,但它提供了字符串数据的内存地址,而不是字符串类/引用,我需要更改以允许使用此方法。我知道字符串是不可改变的,并且不能被改变(虽然你可以,但它不是推荐的),但我不想改变实际的字符串,而是改变它的引用(字符串对象) 。
是否有一些其他方式来获取字符串对象引用的地址?
一些示例代码:
Private oTestperson As New Person
Private Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
' Create the form
AddText("Name", oTestperson.Name)
AddText("Phone", oTestperson.Phone)
AddText("Address", oTestperson.Address)
End Sub
Public Sub AddText(ByVal Title As String, ByRef sValue As String)
Dim oGCHandle As System.Runtime.InteropServices.GCHandle
Dim oInputItem As New InputItem
' This does not do the job, as it only returns the address of the string data, not the reference to the string class
oGCHandle = System.Runtime.InteropServices.GCHandle.Alloc(CType(sValue, Object), System.Runtime.InteropServices.GCHandleType.Pinned)
oInputItem.Pointer = oGCHandle.AddrOfPinnedObject()
oGCHandle.Free()
' Store data
oInputItem.ID = GetID()
oInputItem.Type = InputTypes.Text
oInputItem.BaseValue = sValue
If Not Request.Form(oInputItem.ID) Then oInputItem.Value = Request.Form(oInputItem.ID)
If oInputItem.Value Is Nothing Then oInputItem.Value = sValue
' Save in collection
InputItems.Add(oInputItem)
End Sub
Private Sub linkbuttonSave_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles linkbuttonSave.Click
Save()
End Sub
Public Sub Save()
Dim oTest As New Person
Dim oGCHandle As System.Runtime.InteropServices.GCHandle
Dim NewStrPointer As IntPtr
' Check if something has been changed, in that case update the origional value
For Each oInputItem As InputItem In InputItems
If oInputItem.Value <> oInputItem.BaseValue Then
oGCHandle = GCHandle.Alloc(oInputItem.Value, GCHandleType.Pinned)
NewStrPointer = oGCHandle.AddrOfPinnedObject()
oGCHandle.Free()
' This fails as oInputItem.Pointer is the address of the string data, not the string class
Marshal.WriteInt32(oInputItem.Pointer.ToInt32, NewStrPointer.ToInt32)
End If
Next
End Sub
Private InputItems As New ArrayList
Private Class Person
Public Property Name As String
Public Property Phone As String
Public Property Address As String
End Class
Public Enum InputTypes As Integer
Text = 0
End Enum
Public Class InputItem
Public Property ID As String
Public Property BaseValue As Object
Public Property Value As Object
Public Property Type As InputTypes = 0
Public Property Pointer As IntPtr
End Class
所以实质上你想要的是指针的地址而不是指针指向的地址?这样你就可以直接指向指针通过改变指针的地址引用其他字符串?我在这里丢失了什么吗? – 2011-03-15 16:10:03
这里有不止一个错误,你调用GCHandle.Free()之后,你获得的指针不再指向一个固定的对象。想写这样的代码,然后使用C或C++。C++/CLI是一种很好的语言,可以让你同时执行这两种操作。 – 2011-03-15 17:32:07
正确,我需要指针的地址,而不是指针指向的地址。 GCHandler.Free()我在测试时没有释放处理程序,看起来像制作一个C++“不安全”的dll可能是成为那么可以做到这一点。 – 2011-03-16 07:19:41