为什么会出现"无法找到列0"
//将Datareader内容写入datatable
private   void   filldate(string   gj,string   lx)
{
      DataTable   dt=new   DataTable();
      dt.Columns.Add(new   DataColumn( "pid ",   typeof(Int32)));
      dt.Columns.Add(new   DataColumn( "ptitle ",typeof(string)));
      dt.Columns.Add(new   DataColumn( "ptime ",typeof(string)));
      dt.Columns.Add(new   DataColumn( "phit ",   typeof(Int32)));
      sdr=tool.psearch(gj,lx, "psearch ");//sdr是通过Datareader读取数据
      while(sdr.Read())
{    
    DataRow   dr=dt.NewRow();
            dr[0]=Int32.Parse(sdr[ "pid "].ToString());
    dr[1]=sdr[ "ptitle "].ToString();
    dr[2]=Convert.ToDateTime(sdr[ "ptime "].ToString());
    dr[3]=Int32.Parse(sdr[ "phit "].ToString());
    dt.Rows.Add(dr);
        }
                      sdr.Close();
      this.Session[ "searchtable "]=dt;
}
//创建数据源
private   ICollection   CreateDataSource()  
{
DataRow   dr;
                        DataTable   dtnew=new   DataTable( "currenttable ");
DataTable   dt=(DataTable)this.Session[ "searchtable "];
for   (int   i   =   startIndex;   i   <   (startIndex   +   this.DataGrid2.PageSize);   i++)  
{
dr   =   dtnew.NewRow();
dr[0]   =   Int32.Parse(dt.Rows[i][0].ToString());//这一行每次都报错!!!!!!!!!!!
dr[1]   =   dt.Rows[i][1].ToString();
dr[2]   =   Convert.ToDateTime(dt.Rows[i][2].ToString());
dr[3]   =   Int32.Parse(dt.Rows[i][3].ToString());
dtnew.Rows.Add(dr);
}
DataView   dv   =   new   DataView(dtnew);
return   dv;
}

------解决方案--------------------
新的datatable没有创建列
private ICollection CreateDataSource()
{
DataRow dr;
DataTable dtnew=new DataTable( "currenttable ");
dtnew.Columns.Add(new DataColumn( "pid ", typeof(Int32)));
dtnew.Columns.Add(new DataColumn( "ptitle ",typeof(string)));
dtnew.Columns.Add(new DataColumn( "ptime ",typeof(string)));
dtnew.Columns.Add(new DataColumn( "phit ", typeof(Int32)));
DataTable dt=(DataTable)this.Session[ "searchtable "];
for (int i = startIndex; i < (startIndex + this.DataGrid2.PageSize); i++)
{
dr = dtnew.NewRow();
dr[0] = Int32.Parse(dt.Rows[i][0].ToString());//这一行每次都报错!!!!!!!!!!!
dr[1] = dt.Rows[i][1].ToString();
dr[2] = Convert.ToDateTime(dt.Rows[i][2].ToString());
dr[3] = Int32.Parse(dt.Rows[i][3].ToString());
dtnew.Rows.Add(dr);
}
DataView dv = new DataView(dtnew);
return dv;
}