unity3d调用windows系统对话框选择文件夹的方法

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
 
public class OpenDialogFile
{
    public int structSize = 0;
    public IntPtr dlgOwner = IntPtr.Zero;
    public IntPtr instance = IntPtr.Zero;
    public String filter = null;
    public String customFilter = null;
    public int maxCustFilter = 0;
    public int filterIndex = 0;
    public String file = null;
    public int maxFile = 0;
    public String fileTitle = null;
    public int maxFileTitle = 0;
    public String initialDir = null;
    public String title = null;
    public int flags = 0;
    public short fileOffset = 0;
    public short fileExtension = 0;
    public String defExt = null;
    public IntPtr custData = IntPtr.Zero;
    public IntPtr hook = IntPtr.Zero;
    public String templateName = null;
    public IntPtr reservedPtr = IntPtr.Zero;
    public int reservedInt = 0;
    public int flagsEx = 0;
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
public class OpenDialogDir
{
    public IntPtr hwndOwner = IntPtr.Zero;
    public IntPtr pidlRoot = IntPtr.Zero;
    public String pszDisplayName = null;
    public String lpszTitle = null;
    public UInt32 ulFlags = 0;
    public IntPtr lpfn = IntPtr.Zero;
    public IntPtr lParam = IntPtr.Zero;
    public int iImage = 0;
}
 
public class DllOpenFileDialog
{
    [DllImport("Comdlg32.dll", SetLastError = true, ThrowOnUnmappableChar = true, CharSet = CharSet.Auto)]
    public static extern bool GetOpenFileName([In, Out] OpenDialogFile ofn);
 
    [DllImport("Comdlg32.dll", SetLastError = true, ThrowOnUnmappableChar = true, CharSet = CharSet.Auto)]
    public static extern bool GetSaveFileName([In, Out] OpenDialogFile ofn);
 
    [DllImport("shell32.dll", SetLastError = true, ThrowOnUnmappableChar = true, CharSet = CharSet.Auto)]
    public static extern IntPtr SHBrowseForFolder([In, Out] OpenDialogDir ofn);
 
    [DllImport("shell32.dll", SetLastError = true, ThrowOnUnmappableChar = true, CharSet = CharSet.Auto)]
    public static extern bool SHGetPathFromIDList([In] IntPtr pidl, [In, Out] char[] fileName);
    
}
使用如下：
        OpenDialogDir ofn2 = new OpenDialogDir();
        ofn2.pszDisplayName = new string(new char[2000]); ;     // 存放目录路径缓冲区  
        ofn2.lpszTitle = "Open Project";// 标题  
        //ofn2.ulFlags = BIF_NEWDIALOGSTYLE | BIF_EDITBOX; // 新的样式,带编辑框  
        IntPtr pidlPtr = DllOpenFileDialog.SHBrowseForFolder(ofn2);
 
        char[] charArray = new char[2000];
        for (int i = 0; i < 2000;i++ )
            charArray[i] = '\0';
 
        DllOpenFileDialog.SHGetPathFromIDList(pidlPtr, charArray);
        string fullDirPath = new String(charArray);
        fullDirPath = fullDirPath.Substring(0, fullDirPath.IndexOf('\0'));
 
        Debug.Log(fullDirPath);//这个就是选择的目录路径。