把数据写入到Text中
public static string TableToTextFile(DataTable dt,string FullFileName)
{
string fp=FullFileName;
try
{
using (StreamWriter sw = new StreamWriter(fp))
{
DataRow[] myRow=dt.Select();
//取得数据表各列标题，各标题之间以\t分割，最后一个列标题后加回车符
string title="";
int i;
for(i=0;i<dt.Columns.Count;i++)
{
title+=dt.Columns[i].Caption.ToString()+"\t";
}

sw.WriteLine(title);
string line="";

foreach(DataRow row in myRow)
{
//在当前行中，逐列获得数据，数据之间以\t分割，结束时加回车符\n

line="";
for(i=0;i<row.ItemArray.Length;i++)
{
line+=row[i].ToString()+"\t";
}
sw.WriteLine(line);

}
sw.Close();

}
}
catch(Exception ex)
{
fp="0||"+ex.Message;
}
return fp;
}