打开文件夹

using System;
using System.Collections;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using UnityEngine;

//unity3d调用win32打开对话框
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
public struct OpenFileName
{
    public int structSize;
    public IntPtr dlgOwner;
    public IntPtr instance;
    public string filter;
    public string customFilter;
    public int maxCustFilter;
    public int filterIndex;
    public string file;
    public int maxFile;
    public string fileTitle;
    public int maxFileTitle;
    public string initialDir;  //打开路径     null
    public string title;
    public int flags;
    public short fileOffset;
    public short fileExtension;
    public string defExt;
    public IntPtr custData;
    public IntPtr hook;
    public string templateName;
    public IntPtr reservedPtr;
    public int reservedInt;
    public int flagsEx;
}

public class OpenPDF:MonoBehaviour
{
    [DllImport("Comdlg32.dll", SetLastError = true, ThrowOnUnmappableChar = true, CharSet = CharSet.Auto)]
    private static extern bool GetOpenFileName([In, Out] OpenFileName ofn);

    OpenFileName ofn;


    void Start()
    {
        ofn = new OpenFileName();
        ofn.structSize = Marshal.SizeOf(ofn);
        ofn.filter = "PDF文件(*.pdf)\0*.pdf;";
        ofn.file = new string(new char[256]);
        ofn.maxFile = ofn.file.Length;
        ofn.fileTitle = new string(new char[64]);
        ofn.maxFileTitle = ofn.fileTitle.Length;
        ofn.initialDir = "C:\\";
        ofn.title = "打开课件";
        ofn.defExt = "PDF";
        ofn.flags = 0x00080000 | 0x00001000 | 0x00000800 | 0x00000200 | 0x00000008;   //OFN_EXPLORER|OFN_FILEMUSTEXIST|OFN_PATHMUSTEXIST| OFN_ALLOWMULTISELECT|OFN_NOCHANGEDIR    
    }

    public void OpenFile()
    {
        StartCoroutine(SelectFile());
    }
    IEnumerator SelectFile()
    {
        yield return 1;
        List<string> fliePath = GetFilePath();
        for (int i = 0; i < fliePath.Count; i++)
        {
            Debug.Log(fliePath[i]);
        }
    }

    /// <summary>
    /// 支持同时选择多个文件
    /// </summary>
    /// <returns></returns>
    public List<string> GetFilePath()
    {
        List<string> fliePath = new List<string>();
        if (GetOpenFileName(ofn))
        {
            string[] filePath = ofn.file.Split('\0');// ‘\0’可表示C++中的NULL
            for (int i = 0; i < filePath.Length; i++)
            {
                if (!string.IsNullOrEmpty(filePath[i])&&i!=0)
                {
                    fliePath.Add(filePath[0]+ filePath[i]);
                }
            }
        }
        else
        {
            Debug.Log("取消选择");
        }
        return fliePath;
    }
}