DataGridView ComputeVisibleColumn NullReferenceException [英] DataGridView ComputeVisibleColumn NullReferenceException

问题描述

有时当我对datagridview进行更改时 - 例如删除列，或重命名列标题，或者接受基础数据表上的更改，我得到了空引用异常。

堆栈跟踪在System.Windows.Forms.DataGridView.ComputeVisibleColumns结束并从System开始.Windows.Forms.NativeWindowCallback。

我想尽可能防止这种情况发生或以某种方式捕获它。

我尝试创建一个继承自datagridview的datagridview类，并使用a覆盖跟踪中的一些函数尝试catch捕获异常，但它仍然将其抛出_COMPlusException，或者如果没有地方可以捕获异常，那么它会抛出错误并导致应用程序崩溃。

我不知道该怎么做。

我确实看到这被报告为微软的一个错误但无法复制。我真的很感激有关如何处理这个的任何想法。

System.NullReferenceException：对象引用未设置为对象的实例。<在System.Windows.Forms.DataGridView.ComputeVisibleColumns（）
at System.Windows.Forms.DataGridView.LayoutScrollBars（）
at System.Windows.Forms.DataGridView.ComputeLayout（）
at System。 Windows.Forms.DataGridView.PerformLayoutPrivate（Boolean useRowShortcut，Boolean computeVisibleRows，Boolean invalidInAdjustFillingColumns，Boolean repositionEditingControl）
System.Windows.Forms.DataGridView.OnBandThicknessChanged的System.Windows.Forms.DataGridView.OnColumnWidthChanged（DataGridViewColumnEventArgs e）
（DataGridViewBand dataGridViewBand）
在System.Windows.Forms.DataGridView.AutoResizeColumnInternal（Int32 columnIndex，DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaInternal，Boolean fixedHeight）
at System.Windows.Forms.DataGridView.AutoResizeAllVisibleColumnsInte rnal（DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaFilter，Boolean fixedHeight）
System.Windows.Forms.DataGridView.OnAddedRow_PostNotification（Int32 rowIndex）
at System.Windows.Forms.DataGridViewRowCollection.OnCollectionChanged_PostNotification（CollectionChangeAction cca，Int32 rowIndex，Int32 rowCount，DataGridViewRow dataGridViewRow ，布尔值changeIsDeletion，Boolean changeIsInsertion，Boolean recreateNewRow，Point newCurrentCell）
at System.Windows.Forms.DataGridViewRowCollection.OnCollectionChanged（CollectionChangeEventArgs e，Int32 rowIndex，Int32 rowCount）
at System.Windows.Forms.DataGridViewRowCollection.AddInternal（ DataGridViewRow dataGridViewRow）
System.Windows.Forms.Forms.Forms.DataGridView.DataGridViewDataConnection.ProcessListChanged（ListChangedEventArgs e）
System.Windows.Forms.DataGridView的System.Windows.Forms.DataGridView.RefreshRows（Boolean scrollIntoView） .DataGridViewDataConnection.currencyManager _ListChanged（Object sender，ListChangedEventArgs e）
System.Windows.Forms.CurrencyManager.OnListChanged（ListChangedEventArgs e）
System.Windows.Forms.CurrencyManager.List_ListChanged（Object sender，ListChangedEventArgs e）
at System System.Data.Data.OnListChanged（ListChangedEventArgs e）
System.Data.DataView.UpdateIndex（Boolean force，Boolean fireEvent）
System.Data.Data.UpdateIndex（Boolean force）
System.Data .DataView.SetIndex2（String newSort，DataViewRowState newRowStates，DataExpression newRowFilter，Boolean fireEvent）
System.Data.DataView.SetIndex（String newSort，DataViewRowState newRowStates，DataExpression newRowFilter）
at System.Data.DataView.set_Sort（字符串值）
System.Data.DataView.System.ComponentModel.IBindingList.ApplySort（PropertyDescriptor属性，ListSortDirection方向）

System.Windows.Forms.DataGridView.DataGridViewDataConnection.Sort（DataGridViewColumn dataGridVie） wColumn，ListSortDirection方向）
在System.Windows.Forms.DataGridView.SortInternal（IComparer比较器，DataGridViewColumn dataGridViewColumn，ListSortDirection方向）
在System.Windows.Forms.DataGridView.Sort（DataGridViewColumn dataGridViewColumn，ListSortDirection方向）
System.Windows.Forms.DataGridView.OnColumnHeaderMouseClick（DataGridViewCellMouseEventArgs e）
在System.Windows.Forms.Forms.Control.WmMouseUp的System.Windows.Forms.DataGridView.OnMouseClick（MouseEventArgs e）
中。 m，MouseButtons按钮，Int32单击）
在System.Windows.Forms.Control.WndProc（Message& m）

System.Windows.Forms.DataGridView.WndProc（Message& m）
在System。 Windows.Forms.Control.ControlNativeWindow.OnMessage（Message& m）
System.Windows.Forms.Control.ControlNativeWindow.WndProc（Message& m）
System.Windows.Forms.NativeWindow.Callback（IntPtr hWnd ，Int32 msg，IntPtr wparam，IntPtr lparam）

解决方案

嗨Malkie，

我认为我们需要有关此问题的更多信息以进行故障排除。为了确定问题所在，如果您向我们提供复制步骤，我们将不胜感激。我相信在重现问题后我们可以更接近最终解决方案。

谢谢。

祝福，

Jun Wang

Sometimes when I make a change to the datagridview - such as delete a column, or rename a column header, or acceptchanges on the underlying data table I get a Null Reference exception.

 

The stack trace ends at System.Windows.Forms.DataGridView.ComputeVisibleColumns and starts at System.Windows.Forms.NativeWindowCallback.

 

I want to prevent this from happening if possible or catch it somehow.

 

I tried creating a datagridview class that inherits from the datagridview and override some of the functions in the trace with a try catch to catch the exception but it still throws it up as  _COMPlusException or if there is no place to catch the exception then it throws an error and crashes the application.

 

I don't know what to do about this. 

 

I did see that this was reported as a bug to Microsoft but it could not be reproduced.  I would really appreciate any ideas about how to deal with this.

 

System.NullReferenceException: Object reference not set to an instance of an object.
   at System.Windows.Forms.DataGridView.ComputeVisibleColumns()
   at System.Windows.Forms.DataGridView.LayoutScrollBars()
   at System.Windows.Forms.DataGridView.ComputeLayout()
   at System.Windows.Forms.DataGridView.PerformLayoutPrivate(Boolean useRowShortcut, Boolean computeVisibleRows, Boolean invalidInAdjustFillingColumns, Boolean repositionEditingControl)
   at System.Windows.Forms.DataGridView.OnColumnWidthChanged(DataGridViewColumnEventArgs e)
   at System.Windows.Forms.DataGridView.OnBandThicknessChanged(DataGridViewBand dataGridViewBand)
   at System.Windows.Forms.DataGridView.AutoResizeColumnInternal(Int32 columnIndex, DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaInternal, Boolean fixedHeight)
   at System.Windows.Forms.DataGridView.AutoResizeAllVisibleColumnsInternal(DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaFilter, Boolean fixedHeight)
   at System.Windows.Forms.DataGridView.OnAddedRow_PostNotification(Int32 rowIndex)
   at System.Windows.Forms.DataGridViewRowCollection.OnCollectionChanged_PostNotification(CollectionChangeAction cca, Int32 rowIndex, Int32 rowCount, DataGridViewRow dataGridViewRow, Boolean changeIsDeletion, Boolean changeIsInsertion, Boolean recreateNewRow, Point newCurrentCell)
   at System.Windows.Forms.DataGridViewRowCollection.OnCollectionChanged(CollectionChangeEventArgs e, Int32 rowIndex, Int32 rowCount)
   at System.Windows.Forms.DataGridViewRowCollection.AddInternal(DataGridViewRow dataGridViewRow)
   at System.Windows.Forms.DataGridView.RefreshRows(Boolean scrollIntoView)
   at System.Windows.Forms.DataGridView.DataGridViewDataConnection.ProcessListChanged(ListChangedEventArgs e)
   at System.Windows.Forms.DataGridView.DataGridViewDataConnection.currencyManager_ListChanged(Object sender, ListChangedEventArgs e)
   at System.Windows.Forms.CurrencyManager.OnListChanged(ListChangedEventArgs e)
   at System.Windows.Forms.CurrencyManager.List_ListChanged(Object sender, ListChangedEventArgs e)
   at System.Data.DataView.OnListChanged(ListChangedEventArgs e)
   at System.Data.DataView.UpdateIndex(Boolean force, Boolean fireEvent)
   at System.Data.DataView.UpdateIndex(Boolean force)
   at System.Data.DataView.SetIndex2(String newSort, DataViewRowState newRowStates, DataExpression newRowFilter, Boolean fireEvent)
   at System.Data.DataView.SetIndex(String newSort, DataViewRowState newRowStates, DataExpression newRowFilter)
   at System.Data.DataView.set_Sort(String value)
   at System.Data.DataView.System.ComponentModel.IBindingList.ApplySort(PropertyDescriptor property, ListSortDirection direction)
   at System.Windows.Forms.DataGridView.DataGridViewDataConnection.Sort(DataGridViewColumn dataGridViewColumn, ListSortDirection direction)
   at System.Windows.Forms.DataGridView.SortInternal(IComparer comparer, DataGridViewColumn dataGridViewColumn, ListSortDirection direction)
   at System.Windows.Forms.DataGridView.Sort(DataGridViewColumn dataGridViewColumn, ListSortDirection direction)
   at System.Windows.Forms.DataGridView.OnColumnHeaderMouseClick(DataGridViewCellMouseEventArgs e)
   at System.Windows.Forms.DataGridView.OnMouseClick(MouseEventArgs e)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   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)

解决方案

Hi Malkie,

 

I believe that we need more information about this problem for troubleshooting. In order to make sure where the problem is, it would be appreciated if you provide us the steps of reproducing it. I believe that we can get closer to the final solution after reproducing the problem.

Thanks.

 

Best wishes,

Jun Wang

 

这篇关于DataGridView ComputeVisibleColumn NullReferenceException的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！