求助：并非所有的代码路径都返回值

[whheng]

public static DataTable ConvertDataReaderToDataTable(SqlDataReader dataReader)
{
DataTable datatable = new DataTable();
try
{
for (int i = 0; i < dataReader.FieldCount; i++)
{
DataColumn mydataColumn = new DataColumn();
mydataColumn.DataType = dataReader.GetFieldType(i);
mydataColumn.ColumnName = dataReader.GetName(i);
datatable.Columns.Add(mydataColumn);
}
while (dataReader.Read())
{
DataRow myDataRow = datatable.NewRow();
for (int i = 0; i < dataReader.FieldCount; i++)
{
myDataRow[i] = dataReader[i].ToString();
}
datatable.Rows.Add(myDataRow);
myDataRow = null;
}
dataReader.Close();
return datatable;
}
catch (Exception ex)
{
Console.WriteLine("error:" + ex.ToString());
}
}

错误 1 “SystemTools.ConvertDataReaderToDataTable(System.Data.SqlClient.SqlDataReader)”: 并非所有的代码路径都返回值

[jrl5365]

return null;

[nj_1st_excellence]

catch (Exception ex) 
{ 
   Console.WriteLine("error:" + ex.ToString()); 
   return datatable;
} 

[superaremeng]

catch (Exception ex)
{
Console.WriteLine("error:" + ex.ToString());
}
return datatable;

[wangkun9999]

public static DataTable ConvertDataReaderToDataTable(SqlDataReader dataReader) 
    { 
        DataTable datatable = new DataTable(); 
        try 
        { 
            for (int i = 0; i  < dataReader.FieldCount; i++) 
            { 
                DataColumn mydataColumn = new DataColumn(); 
                mydataColumn.DataType = dataReader.GetFieldType(i); 
                mydataColumn.ColumnName = dataReader.GetName(i); 
                datatable.Columns.Add(mydataColumn); 
            } 
            while (dataReader.Read()) 
            { 
                DataRow myDataRow = datatable.NewRow(); 
                for (int i = 0; i  < dataReader.FieldCount; i++) 
                { 
                    myDataRow[i] = dataReader[i].ToString(); 
                } 
                datatable.Rows.Add(myDataRow); 
                myDataRow = null; 
            } 
            dataReader.Close(); 
          } 
        catch (Exception ex) 
        { 
            Console.WriteLine("error:" + ex.ToString()); 
        } 
       return datatable; //放在函数外面.

    } 

[mohugomohu]

public static DataTable ConvertDataReaderToDataTable(SqlDataReader dataReader) 
    { 
        DataTable datatable = new DataTable(); 
        try 
        { 
            for (int i = 0; i  < dataReader.FieldCount; i++) 
            { 
                DataColumn mydataColumn = new DataColumn(); 
                mydataColumn.DataType = dataReader.GetFieldType(i); 
                mydataColumn.ColumnName = dataReader.GetName(i); 
                datatable.Columns.Add(mydataColumn); 
            } 
            while (dataReader.Read()) 
            { 
                DataRow myDataRow = datatable.NewRow(); 
                for (int i = 0; i  < dataReader.FieldCount; i++) 
                { 
                    myDataRow[i] = dataReader[i].ToString(); 
                } 
                datatable.Rows.Add(myDataRow); 
                myDataRow = null; 
            } 
            dataReader.Close(); 
            return datatable; 
        } 
        catch (Exception ex) 
        { 
            Console.WriteLine("error:" + ex.ToString()); 
            return;//这里返回
        } 
    } 

[rtsp]

在最后加个return null;

[whheng]

谢谢！