string path = EditorUtility.OpenFilePanel("Load png Textures of Directory", "", "");WWW ww=new WWW("file:///"+path);print(ww.url);yield return ww;gui.texture=ww.texture;

OpenFileDialog ofd = new OpenFileDialog();   //new一个方法 ofd.InitialDirectory ="file://"+UnityEngine.Application.dataPath;  //定义打开的默认文件夹位置//定义打开的默认文件夹位置if(ofd.ShowDialog()==DialogResult.OK){      //显示打开文件的窗口      Debug.Log( ofd.FileName);}

using UnityEngine;using System.Collections;using System.Text;using System.Runtime.InteropServices;using System;public class Test : MonoBehaviour {    public GameObject plane;    void OnGUI()    {        if(GUI.Button(new Rect(0,0,100,35),"OpenDialog"))        {            OpenFileName ofn = new OpenFileName();            ofn.structSize = Marshal.SizeOf(ofn);            ofn.filter = "All Files\0*.*\0\0";            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 =UnityEngine.Application.dataPath;//默认路径            ofn.title = "Open Project";            ofn.defExt = "JPG";//显示文件的类型           //注意 一下项目不一定要全选 但是0x00000008项不要缺少            ofn.flags=0x00080000|0x00001000|0x00000800|0x00000200|0x00000008;//OFN_EXPLORER|OFN_FILEMUSTEXIST|OFN_PATHMUSTEXIST| OFN_ALLOWMULTISELECT|OFN_NOCHANGEDIR            if(DllTest.GetOpenFileName( ofn ))            {                StartCoroutine(WaitLoad(ofn.file));//加载图片到panle                Debug.Log( "Selected file with full path: {0}"+ofn.file );            }        }    }    IEnumerator WaitLoad(string fileName)    {        WWW wwwTexture=new WWW("file://"+fileName);        Debug.Log(wwwTexture.url);        yield return wwwTexture;        plane.renderer.material.mainTexture=wwwTexture.texture;    }}

参考知识：1、http://msdn.microsoft.com/en-us/library/system.runtime.interopservices.inattribute%28v=vs.85%29
         2、http://msdn.microsoft.com/en-us/library/windows/desktop/ms646839%28v=vs.85%29.aspx
         3、C#和win32类型对应
         4、http://blog.csdn.net/wanfang323/article/details/6372995