Question

我使用以下代码填充数据集

public static DataSet GetDataSetBySP(string spName)
    {
        try
        {
            using (SqlConnection conn = new SqlConnection(ConnString))
            {
                conn.Open();
                SqlCommand cmd = conn.CreateCommand();
                cmd.CommandType = CommandType.StoredProcedure;
                cmd.CommandText = spName;
                cmd.CommandTimeout = 60;
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                DataSet ds = new DataSet();
                da.Fill(ds);

                conn.Close();
                return ds;
            }
        }
        catch
        {
            return null;
        }
    }

在我第一次调用该函数时，我只得到第一个填充数据的表，其他的将如下所示 enter image description here

，Data Visualizer中的错误就像

DataSet Visualizer

Unhandled exception has occurred in a component in your application.If you click Continue,the application will ignore this error and attempt to continue.

Object referance not set to an instance of an object


See the end of this message for details on invoking 
just-in-time (JIT) debugging instead of this dialog box.

************** Exception Text **************
System.NullReferenceException: Object reference not set to an instance of an object.
   at EnhancedDataSetVisualizer.VisualizerCommunicator.GetTableCellValue(Int32 rowIndex, Int32 colIndex)
   at EnhancedDataSetVisualizer.DataSetForm.dataGridView_CellValueNeeded(Object sender, DataGridViewCellValueEventArgs e)
   at System.Windows.Forms.DataGridView.OnCellValueNeeded(DataGridViewCellValueEventArgs e)
   at System.Windows.Forms.DataGridView.OnCellValueNeeded(Int32 columnIndex, Int32 rowIndex)
   at System.Windows.Forms.DataGridViewCell.GetValue(Int32 rowIndex)
   at System.Windows.Forms.DataGridViewCell.PaintWork(Graphics graphics, Rectangle clipBounds, Rectangle cellBounds, Int32 rowIndex, DataGridViewElementStates cellState, DataGridViewCellStyle cellStyle, DataGridViewAdvancedBorderStyle advancedBorderStyle, DataGridViewPaintParts paintParts)
   at System.Windows.Forms.DataGridViewRow.PaintCells(Graphics graphics, Rectangle clipBounds, Rectangle rowBounds, Int32 rowIndex, DataGridViewElementStates rowState, Boolean isFirstDisplayedRow, Boolean isLastVisibleRow, DataGridViewPaintParts paintParts)
   at System.Windows.Forms.DataGridViewRow.Paint(Graphics graphics, Rectangle clipBounds, Rectangle rowBounds, Int32 rowIndex, DataGridViewElementStates rowState, Boolean isFirstDisplayedRow, Boolean isLastVisibleRow)
   at System.Windows.Forms.DataGridView.PaintRows(Graphics g, Rectangle boundingRect, Rectangle clipRect, Boolean singleHorizontalBorderAdded)
   at System.Windows.Forms.DataGridView.PaintGrid(Graphics g, Rectangle gridBounds, Rectangle clipRect, Boolean singleVerticalBorderAdded, Boolean singleHorizontalBorderAdded)
   at System.Windows.Forms.DataGridView.OnPaint(PaintEventArgs e)
   at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer, Boolean disposeEventArgs)
   at System.Windows.Forms.Control.WmPaint(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.DataGridView.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)


************** Loaded Assemblies **************
mscorlib
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000)
    CodeBase: file:///C:/WINDOWS/Microsoft.NET/Framework/v2.0.50727/mscorlib.dll
----------------------------------------
Microsoft.VisualStudio.CommonIDE
    Assembly Version: 9.0.0.0
    Win32 Version: 9.0.30729.1
    CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/Microsoft.VisualStudio.CommonIDE/9.0.0.0__b03f5f7f11d50a3a/Microsoft.VisualStudio.CommonIDE.dll
----------------------------------------
System.Windows.Forms
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000)
    CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Windows.Forms/2.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
----------------------------------------
System
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000)
    CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System/2.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
System.Drawing
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000)
    CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Drawing/2.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
----------------------------------------
System.Configuration
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000)
    CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Configuration/2.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll
----------------------------------------
System.Xml
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000)
    CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Xml/2.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------
Microsoft.VisualStudio.DebuggerVisualizers
    Assembly Version: 9.0.0.0
    Win32 Version: 9.0.30729.1
    CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/Microsoft.VisualStudio.DebuggerVisualizers/9.0.0.0__b03f5f7f11d50a3a/Microsoft.VisualStudio.DebuggerVisualizers.dll
----------------------------------------
Microsoft.VisualStudio.Debugger.DataSetVisualizer
    Assembly Version: 9.0.0.0
    Win32 Version: 9.0.30729.1
    CodeBase: file:///C:/Program%20Files/Microsoft%20Visual%20Studio%209.0/Common7/Packages/Debugger/Visualizers/Microsoft.VisualStudio.Debugger.DataSetVisualizer.dll
----------------------------------------
System.Data
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000)
    CodeBase: file:///C:/WINDOWS/assembly/GAC_32/System.Data/2.0.0.0__b77a5c561934e089/System.Data.dll
----------------------------------------

************** JIT Debugging **************
To enable just-in-time (JIT) debugging, the .config file for this
application or computer (machine.config) must have the
jitDebugging value set in the system.windows.forms section.
The application must also be compiled with debugging
enabled.

For example:

<configuration>
    <system.windows.forms jitDebugging="true" />
</configuration>

When JIT debugging is enabled, any unhandled exception
will be sent to the JIT debugger registered on the computer
rather than be handled by this dialog box.

谁能告诉我为什么我会看到这个？但是第二次当我刷新我的aspx页面时，我正在使用适当的数据获得所有表格。

提前致谢

新修改

大家好，谢谢快速回复。但是我没有在catch中得到任何错误。数据集完全填满成功，即使第一个表的数据我正在得到正确，但是我发现这个例外的其余部分不是代码。

最新更新

另外我在另一个测试中发现，数据集Visualizer没有显示数据表mote那个。它包含记录/表但仍然显示上面的一个错误。可能是由于某些问题

Answer 1

猜测一下，很有可能发生异常，因为你有......

     catch
    {
        return null;
    }

UI无法呈现null DataSet。我建议检查是否引发了异常，如果是，请查看其消息，以查看连接到数据库或使用记录填充DataSet是否存在问题。

修改

由于你确认在catch块中没有异常，我快速浏览了一下，Visual Studio可能存在问题。有MSDN forum entry看起来像是同一个问题。

还有一个connect issue logged，他们说这个问题已在Visual Studio 2010中修复，你能否在2010年重现这个问题（如果你有权访问它？）

Answer 2

您是否在检查返回值是否为空？您的函数可能有一些异常。我会重新抓住部分

    catch
    {
        return new DataSet();
    }

甚至更好，我会做一些错误事件，会显示一些错误的消息框。

    catch(Exception exc)
    {
        Error(exc);
        return new DataSet();
    }

Answer 3

我的猜测是，它与此有关：

catch
{
    return null;
}

这意味着无论出现什么问题，你都会忽略这个问题（甚至不记录它），只返回null。任何尝试使用返回值而不检查无效的东西都会给出你已经显示的异常。

你应该从不拥有这种一揽子“抓住所有并忽略”的处理程序。如果你真的想要捕获所有异常（这在调用堆栈的根目录下是合理的）那么你应该总是记录异常 - 那时你不应该再尝试做了工作

在这种情况下，您可能应该有一个异常处理程序更高，但是根本没有捕获异常 - 让它冒泡堆栈，但通过中止处理更高级别的异常当前的用户操作。假装什么都没有出错，但是给出了目前显然无法处理的返回值，这不是一个好主意。

我会敦促你不返回一个空的DataSet - 我会说这可能是不恰当的“处理”错误，因为你真的不知道如何处理它。

对象引用未设置为对象的实例在数据集中

3 个答案: