Jeff 隨手記

{
    DataTable dt = new DataTable();
    dt.Columns.Add("FileName");
    dt.Columns.Add("FileExtension");
    dt.Columns.Add("FileSize");
    DirectoryInfo di = new DirectoryInfo("c:\\PICDemo");
    foreach (FileSystemInfo fsi in di.GetFileSystemInfos())
    {
        FileInfo fi = new FileInfo(fsi.FullName);
        DataRow dr = dt.NewRow();
        dr["FileName"] = fsi.Name; //取得檔案名稱
        dr["FileExtension"] = fsi.Extension; //取得副檔名
        dr["FileSize"] = fi.Length; //取得檔案大小
        dt.Rows.Add(dr);
    }
    DataSet ds = new DataSet();
    ds.Tables.Add(dt);
    return ds;
}

/// 取得圖片資料 
/// </summary> 
/// <param name="FileName">欲下載的檔案名稱</param> 
/// <param name="OffSet">位置</param> 
/// <param name="ChunkSize"一次下次的資料量></param> 
/// <returns>byte[]</returns> 
public byte[] GetPic(string FileName, int OffSet, int ChunkSize) 
{ 
    try 
    { 
        byte[] bt; 
        using (FileStream fs = new FileStream(Path.Combine(@"c:\\PICDemo", FileName), FileMode.Open, FileAccess.Read, FileShare.ReadWrite)) 
        { 
            fs.Seek(OffSet, SeekOrigin.Begin); 

            if ((OffSet + ChunkSize) > fs.Length) 
            { 
                ChunkSize = Convert.ToInt32(fs.Length - OffSet); 
            } 
            if (ChunkSize <= 0) 
            { 
                bt = new byte[0]; 
                return bt; 
            } 
            bt = new byte[ChunkSize]; 
            fs.Read(bt, 0, ChunkSize); 
            fs.Close(); 
        } 
        return bt; 
    } 
    catch (Exception ex) 
    { 
        throw ex; 
    } 
}

{
	if (gridList.Rows.Count == 0) return;
	this.Cursor = Cursors.WaitCursor;
	Stopwatch sw = new Stopwatch();
	sw.Start();//計時開始
	WSPic.Service1Client sc = new WCFPicClient.WSPic.Service1Client();
	//這時的sc.State=Created
	try
	{
		progressBar1.Value = 0;
		int OffSet = 0;
		int FileSize = Convert.ToInt32(gridList.CurrentRow.Cells[2].Value);//檔案大小
		
		//取得MaxReceivedMessageSize的設定值
		BindingElementCollection bec=sc.Endpoint.Binding.CreateBindingElements();
		TransportBindingElement tbe = bec.Find<TransportBindingElement>();

		int ChunkSize = Convert.ToInt32(tbe.MaxReceivedMessageSize * 0.7);
		//一次下載的量,MaxReceivedMessageSize*0.7的原因是它還含其它訊息,不可能百分之百都只放圖檔的byte[]
		int Rate = 0;
		string FileName = gridList.CurrentRow.Cells[0].Value.ToString();
		byte[] PicData=new byte[0];
		using (MemoryStream ms = new MemoryStream(FileSize))
		{
			string strErr = "";

			int RtyTimes = 0;//失敗重試次數
			int MaxRtyTimes = 3;//允許最多可重試次數
			do
			{
				try
				{
					PicData = sc.GetPic(FileName, OffSet, ChunkSize);//從Web Service取得圖檔資料
					//這時的sc.State=Opened
					ms.Write(PicData, 0, PicData.Length);
					//把從Web Service取回來的byte[] 寫到Memory Stream裡去.

					OffSet += ChunkSize;//已成功接收到,就將Offset移至下一個點

					Rate = Convert.ToInt32((OffSet * 100) / FileSize);//已完成傳輸百分比
					Rate = Rate > 100 ? 100 : Rate;//避免破百的情況發生
					progressBar1.Value = Rate;
				}
				catch (Exception ex)
				{
					strErr = ex.Message;//將錯誤訊息儲存起來
					if (RtyTimes == MaxRtyTimes)
					{//如果連續傳輸到最多可重試次數,就不傳了
						break;
					}
					else
					{//累加失敗次數
						RtyTimes++;
					}
				}
			}
			while (PicData.Length > 0);//讀到沒有資料為止

			picFromWS.Image = Image.FromStream(ms);//顯示圖檔
			if (strErr.Length > 0)
			{
				MessageBox.Show(strErr
								, string.Format("傳輸過程發生 {0} 次失敗", RtyTimes)
								, MessageBoxButtons.OK
								, RtyTimes == MaxRtyTimes ? MessageBoxIcon.Error : MessageBoxIcon.Warning
								//傳輸成功,但過程中有失贁過,Icon用Warning就好,傳輸失敗再用Error的Icon
								);
			}
		}
	}
	catch (Exception ex)
	{
		MessageBox.Show(ex.Message);
	}
	finally 
	{
		if (sc.State == System.ServiceModel.CommunicationState.Opened || sc.State == System.ServiceModel.CommunicationState.Opening)
		{
			sc.Close();
			//這時的sc.State=Closed;
		}
		this.Cursor = Cursors.Default;
	}
	sw.Stop();//計時結束
	txtTime.Text = sw.Elapsed.ToString();
}