Question

我应该如何在VB.NET中导入DLL？一个例子是：

<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
Private Shared Function GetWindowText(ByVal hwnd As IntPtr, ByVal lpString As StringBuilder, ByVal cch As Integer) As Integer

End Function

如果我把它放在Class或其他地方，我会得到“DLLimport未定义”我正在使用Visual Studio 2008 Professional

Answer 1

您必须将Imports System.Runtime.InteropServices添加到源文件的顶部。

或者，您可以完全限定属性名称：

<System.Runtime.InteropService.DllImport("user32.dll", _
    SetLastError:=True, CharSet:=CharSet.Auto)> _

Answer 2

Imports System.Runtime.InteropServices

Answer 3

我在pinvoke.net上的 getwindowtext (user32) 中看到，您可以放置一个MarshalAs语句来声明StringBuffer等效于LPSTR。

<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Ansi)> _
Public Function GetWindowText(hwnd As IntPtr, <MarshalAs(UnManagedType.LPStr)>lpString As System.Text.StringBuilder, cch As Integer) As Integer
End Function

Answer 4

你也可以尝试这个

Private Declare Function GetWindowText Lib "user32.dll" (ByVal hwnd As IntPtr, ByVal lpString As StringBuilder, ByVal cch As Integer) As Integer

我总是使用声明功能而不是 DllImport ... 它更简单，更短，并且相同

Answer 5

我知道这已经得到了解答，但是这里有一个例子，供尝试在vb项目中使用SQL Server类型的人使用：

public void Main()
{
    string path = @"drive"; // TODO  
    ApplyAllFiles(path, ProcessFile);
}    

public void ProcessFile(string path) 
{
    /* ... */
}

public void ApplyAllFiles(string folder, Action<string> fileAction)
{
    System.Collections.ArrayList FileList = new System.Collections.ArrayList();
    List<string> logger = new List<string>();

    DateTime DateFilter = DateTime.Now.AddMonths(-6);

    foreach (string file in Directory.GetDirectories(folder))
    {
        fileAction(file);
    }
    foreach (string subDir in Directory.GetDirectories(folder))
    {
        string rootfolder = "root folder";

        if (subDir.Contains(rootfolder))
        {   
            FileList.Add(subDir);
            Dts.Variables["User::objDirectoryList"].Value = FileList;
           //MessageBox.Show(subDir);
        }
        try
        {
            ApplyAllFiles(subDir, fileAction);
        }
        catch (UnauthorizedAccessException e)
        {
            logger.Add(e.Message);

        }
        catch (System.IO.DirectoryNotFoundException e)
        {
            logger.Add(e.Message);
        }
    }
}

如何在VB.NET中使用<dllimport>？</dllimport>

5 个答案: