关于stream的问题。web services 传递附件。请高手指点！

[harron]

wse中有这样的例子，
[WebMethod]
public void CreateDimedImage()
{
SoapContext respContext = HttpSoapContext.ResponseContext;
DimeAttachment dimeAttach = new DimeAttachment(
"image/gif", TypeFormatEnum.MediaType,
@"C:\images\test.gif");
respContext.Attachments.Add(dimeAttach);
}
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调用
Private void btnGetImage_Click(object sender, System.EventArgs e)
{
MyDimeService svc = new MyDimeService();
svc.CreateDimedImage();
if (svc.ResponseSoapContext.Attachments.Count == 1)
{
MessageBox.Show("Got it!\n");
pbDime.Image = new Bitmap(
svc.ResponseSoapContext.Attachments[0].Stream);
}
}
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我想问的是，如果是其他类型的文件，比如文本文件，word文件等，如何写一个通用的函数呢？
调用函数直接将 数据 保存为 文件。
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或者，svc.ResponseSoapContext.Attachments[0].Stream 类型就是stream，
我想请问，直接将stream类型的数据写成一个文件，如何操作？？？
我这样写了下。有问题，我对流弄不明白。唉
StreamWriter objWriter=new StreamWriter(@"d:\good.txt",true,Encoding.GetEncoding("gb2312"));
const int size = 4096;
byte[] bytes = new byte[4096];
int numBytes;
Stream str =svc.ResponseSoapContext.Attachments[0].Stream;
while((numBytes = str.Read(bytes, 0, size)) > 0) <---需要byte类型

objWriter.Write(bytes,0,numBytes); <---需要char类型
objWriter.Close();

[cyp503]

private void CreateFile(string path,System.IO.Stream stream)
{
if(path==null || path=="")
throw new Exception("文件路径不能为空");
if(stream==null)
throw new Exception("附件为空!");
try
{
System.IO.BinaryReader reader = new System.IO.BinaryReader(stream,System.Text.Encoding.Default);
System.IO.BinaryWriter writer = new System.IO.BinaryWriter(System.IO.File.Open(path.Trim() ,System.IO.FileMode.Create ));
if(writer!=null)
{

#region 保存文件
Byte[] bytes = new Byte[4096];
int pos=0;
while(true)
{
int cc=reader.Read(bytes,0,4096);
if(cc>0)
{
writer.Write(bytes,0,cc);
pos+=cc;
}
else
break;
}
reader.Close();
writer.Close();

#endregion
}
}
catch(Exception ex)
{
throw(ex);
}

}