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社区首页 >问答首页 >“字段的子列表...无法创建”是什么意思？

问“字段的子列表...无法创建”是什么意思？
EN

Stack Overflow用户
提问于 2009-07-15 09:31:00
回答 2查看 13.5K关注 0票数 3

我的C#编码应用程序使用Infragistics.Win.UltraWinGrid.UltraGrid来显示一些数据。这些数据基本上是计算机的集合。应用程序能够过滤这些计算机(如“工作站”、“服务器”等)以供查看。我是这样过滤的：

代码语言：javascript
复制
private DataView FilterTableDataForViewing(DataTable originalTable, string filterString, UltraGrid viewGrid)
    {
        DataView dataView = new DataView(originalTable);
        dataView.RowStateFilter = DataViewRowState.CurrentRows;
        dataView.RowFilter = filterString;

        DataTable filteredTable = dataView.ToTable(originalTable.TableName + "_" + dataView.RowFilter);
        viewGrid.DataSource = filteredTable;
        gridDiscoveryMain.DisplayLayout.ViewStyleBand = ViewStyleBand.OutlookGroupBy;
        SetFlagImagesAndColumnWidthsOfDiscoveryGrid();
        return dataView;
    }

注意，我将表名设置为一个可能很大的筛选器字符串。

这就是我如何使用上面的方法：

代码语言：javascript
复制
string filterString = "([Build] = '4.0' AND NOT([OS Plus Version] LIKE '%Server%'))";
            filterString += " OR ([Build] = '4.10')";
            filterString += " OR ([Build] = '4.90')";
            filterString += " OR ([Build] = '5.0' AND NOT([OS Plus Version] LIKE '%Server%'))";
            filterString += " OR ([Build] = '5.1')";
            filterString += " OR ([Build] = '6.0' AND ";
            filterString += "(NOT([OS Plus Version] LIKE '%Server%')) OR (NOT([OS] LIKE '%Server%')))";
            FilterTableDataForViewing(dataSet.Tables["DiscoveryData"], filterString, gridDiscoveryMain);

在此之前，一切都很好。UltraGrids有一个工具，允许您选择要隐藏的列并创建新的自定义列。当此工具启动时，将触发一个名为BeforeColumnChooserDisplayed的UltraGrid事件。这是我的处理程序：

代码语言：javascript
复制
private void gridDiscoveryMain_BeforeColumnChooserDisplayed(object sender, BeforeColumnChooserDisplayedEventArgs e)
    {
        if (gridDiscoveryMain.DataSource == null)
            return;

        e.Cancel = true;
        gridDiscoveryMain.DisplayLayout.Override.RowSelectors = DefaultableBoolean.True;
        gridDiscoveryMain.DisplayLayout.Override.RowSelectorHeaderStyle = RowSelectorHeaderStyle.ColumnChooserButton;
        ShowCustomColumnChooserDialog();
        this.customColumnChooserDialog.CurrentBand = e.Dialog.ColumnChooserControl.CurrentBand;
        this.customColumnChooserDialog.ColumnChooserControl.Style = ColumnChooserStyle.AllColumnsWithCheckBoxes;
    }

下面是ShowCustomColumnChooserDialog方法的实现：

代码语言：javascript
复制
private void ShowCustomColumnChooserDialog()
    {
        DataTable originalTable = GetUnderlyingDataSource(gridDiscoveryMain);
        if (this.customColumnChooserDialog == null || this.customColumnChooserDialog.IsDisposed)
        {
            customColumnChooserDialog = new CustomColumnChooser(ManageColumnDeleted);
            customColumnChooserDialog.Owner = Parent.FindForm();
            customColumnChooserDialog.Grid = gridDiscoveryMain;
        }

        this.customColumnChooserDialog.Show();
    }

customColumnChooserDialog基本上是一个表单，它在InFragurs默认表的基础上增加了一点额外的内容。它的代码处理的最重要的事情就是这个方法：

代码语言：javascript
复制
private void InitializeBandsCombo( UltraGridBase grid )
    {
        this.ultraComboBandSelector.SetDataBinding( null, null );
        if ( null == grid )
            return;

        // Create the data source that we can bind to UltraCombo for displaying 
        // list of bands. The datasource will have two columns. One that contains
        // the instances of UltraGridBand and the other that contains the text
        // representation of the bands.
        UltraDataSource bandsUDS = new UltraDataSource( );
        bandsUDS.Band.Columns.Add( "Band", typeof( UltraGridBand ) );
        bandsUDS.Band.Columns.Add( "DisplayText", typeof( string ) );

        foreach ( UltraGridBand band in grid.DisplayLayout.Bands )
        {
            if ( ! this.IsBandExcluded( band ) )
            {
                bandsUDS.Rows.Add( new object[] { band, band.Header.Caption } );
            }
        }

        this.ultraComboBandSelector.DisplayMember = "DisplayText";
        this.ultraComboBandSelector.ValueMember= "Band";
        this.ultraComboBandSelector.SetDataBinding( bandsUDS, null );

        // Hide the Band column.
        this.ultraComboBandSelector.DisplayLayout.Bands[0].Columns["Band"].Hidden = true;

        // Hide the column headers.
        this.ultraComboBandSelector.DisplayLayout.Bands[0].ColHeadersVisible = false;

        // Set some properties to improve the look & feel of the ultra combo.
        this.ultraComboBandSelector.DropDownWidth = 0;
        this.ultraComboBandSelector.DisplayLayout.Override.HotTrackRowAppearance.BackColor = Color.LightYellow;
        this.ultraComboBandSelector.DisplayLayout.AutoFitStyle = AutoFitStyle.ResizeAllColumns;
        this.ultraComboBandSelector.DisplayLayout.BorderStyle = UIElementBorderStyle.Solid;
        this.ultraComboBandSelector.DisplayLayout.Appearance.BorderColor = SystemColors.Highlight;
    }

如果我单步执行代码，在退出事件处理程序(控件返回到窗体的点)之前，一切都很酷。当我尝试从一个显示filtered的网格中显示CustomColumnChooser对话框时，我得到了一个抛出的。不是那种在代码中显示有问题的行的类型，而是那种显示“微软.NET框架”错误消息框的类型，该消息框显示“您的应用程序中发生了未处理的异常...”。这意味着我不能追踪是什么引起的。这个应用程序在那之后不会崩溃，但想要成为CustomColumnChooser的对话框出现了一个容器，里面只有一个白色的背景和一个大大的红色"X“。

和堆栈跟踪：

代码语言：javascript
复制
See the end of this message for details on invoking 
just-in-time (JIT) debugging instead of this dialog box.

************** Exception Text **************
System.ArgumentException: Child list for field DiscoveryData_([Build] = '4 cannot be created.
   at System.Windows.Forms.BindingContext.EnsureListManager(Object dataSource, String dataMember)
   at System.Windows.Forms.BindingContext.EnsureListManager(Object dataSource, String dataMember)
   at System.Windows.Forms.BindingContext.EnsureListManager(Object dataSource, String dataMember)
   at System.Windows.Forms.BindingContext.EnsureListManager(Object dataSource, String dataMember)
   at System.Windows.Forms.BindingContext.EnsureListManager(Object dataSource, String dataMember)
   at System.Windows.Forms.BindingContext.EnsureListManager(Object dataSource, String dataMember)
   at System.Windows.Forms.BindingContext.EnsureListManager(Object dataSource, String dataMember)
   at System.Windows.Forms.BindingContext.get_Item(Object dataSource, String dataMember)
   at Infragistics.Win.UltraWinGrid.UltraGridLayout.ListManagerUpdated(BindingManagerBase bindingManager)
   at Infragistics.Win.UltraWinGrid.UltraGridLayout.ListManagerUpdated()
   at Infragistics.Win.UltraWinGrid.UltraGridBase.Set_ListManager(Object newDataSource, String newDataMember)
   at Infragistics.Win.UltraWinGrid.UltraGridBase.SetDataBindingHelper(Object dataSource, String dataMember, Boolean hideNewColumns, Boolean hideNewBands)
   at Infragistics.Win.UltraWinGrid.UltraGridBase.SetDataBinding(Object dataSource, String dataMember, Boolean hideNewColumns, Boolean hideNewBands)
   at Infragistics.Win.UltraWinGrid.UltraGridBase.SetDataBinding(Object dataSource, String dataMember, Boolean hideNewColumns)
   at Infragistics.Win.UltraWinGrid.UltraGridBase.SetDataBinding(Object dataSource, String dataMember)
   at Infragistics.Win.UltraWinGrid.UltraGridColumnChooser.CreateColumnChooserGridDataStructure()
   at Infragistics.Win.UltraWinGrid.UltraGridColumnChooser.Initialize()
   at Infragistics.Win.UltraWinGrid.UltraGridColumnChooser.VerifyInitialized()
   at Infragistics.Win.UltraWinGrid.ColumnChooserGridCreationFilter.BeforeCreateChildElements(UIElement parent)
   at Infragistics.Win.UIElement.VerifyChildElements(ControlUIElementBase controlElement, Boolean recursive)
   at Infragistics.Win.UltraWinGrid.UltraGridUIElement.VerifyChildElements(ControlUIElementBase controlElement, Boolean recursive)
   at Infragistics.Win.UIElement.VerifyChildElements(Boolean recursive)
   at Infragistics.Win.UltraWinGrid.UltraGridUIElement.InternalInitializeRect(Boolean verify)
   at Infragistics.Win.UltraWinGrid.UltraGridLayout.GetUIElement(Boolean verify, Boolean forceInitializeRect)
   at Infragistics.Win.UltraWinGrid.UltraGrid.OnPaint(PaintEventArgs pe)
   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.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)

字段Build的Build子列表(DiscoveryData= '4 cannot be created不是很有用。它到底是什么意思？)

c#
infragistics
system.data
EN

回答 2

Stack Overflow用户

回答已采纳

发布于 2009-07-23 13:05:54

我对WinForms不是很了解，也从来没有用过Infragistics。我的猜测是字段DiscoverData(Build = '4 )的Build子列表在一些数据绑定代码中被抛出到框架的深层，它似乎是在寻找名为(Build = '4 )的类的子成员，因为它在字符串文字中的点号或句点(.)处停止。

我尽量避免使用DataSets和DataViews，因为它们会跳过一些疯狂的圈套。

可能值得启动Reflector并在System.Windows.Forms.BindingContext周围戳一戳

票数 2
EN

Stack Overflow用户

发布于 2011-12-09 00:36:31

看看你，DataBindings。

这个问题通常是由你的绑定路径引起的。如果你有这样的东西：

代码语言：javascript
复制
labelFirstName.DataBindings.Add("Text", "_Person.Info.FName", true, DataSourceUpdateMode.OnPropertyChanged);

您可能必须将其更新为另一个Add-method重载：

代码语言：javascript
复制
labelFirstName.DataBindings.Add("Text", _Person.Info, "FName", true, DataSourceUpdateMode.OnPropertyChanged);
票数 0
EN
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：

https://stackoverflow.com/questions/1130364

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