delphi - FMX TListbox(Grid Metropolis UI)中的项目选择不正确

Question

我遇到了在我的应用程序中使用表单中的 TListBox 时，在 HorzScrollBox 中选择不正确的项目的问题。该表单上有两个(或更多)TListBox。它们彼此远离放置，使得它们的绝对左坐标差大于当前设备屏幕宽度的宽度。该错误出现在以下用户操作序列中。

1. 从左侧 TListBox 中选择了一个项目
2. HorzScrollBox 向右滚动，第二个 TListBox 对用户可见，而左侧则不可见。
3. HorzScrollBox 向左滚动。
4. 从左侧 TListBox 中选择了一个新项目。

我们得到如下图:新项目已被选中，但即使我们上下滚动框，所选内容仍会绘制在先前所选项目的位置上。

可以通过非常简单的方式重现该错误。

1. 创建一个新的 Grid MetropolisUI 应用程序。
2. 将左侧的标准 TListBox 替换为新的(速度会更快)。
3. 将表单宽度设置为大于屏幕宽度
4. 将第二个新 TListBox 放置在 HorzScrollBox 中，这样左右 TListboxes 就不会同时看到，并且只有在滚动 HorzScrollBox 后才可以选择项目。
5. 从任何来源(例如两个 TPrototypeBindSource )填充它们，并将创建的 ListItemStyle 的 LinkFieldControlToField 属性设置为 MetropolisUI 。

完成。当您运行该应用程序时，您会遇到问题。仅当您滚动 HorzScrollBox 时才会出现该错误，这样当您在第一个 ListBox 中选择某个项目时就不会看到第二个 HorzScrollBox。否则，将正确选择项目(即使您滚动 ojit_code )。这是表单的资源(除了样式的二进制文件，它需要存在才能重现错误)。

object GridViewForm: TGridViewForm
  Left = 0
  Top = 0
  Caption = 'Grid Form'
  ClientHeight = 946
  ClientWidth = 2600
  StyleBook = StyleBook2
  FormFactor.Width = 1280
  FormFactor.Height = 1024
  FormFactor.Devices = [dkDesktop]
  FormFamily = 'Main'
  FullScreen = True
  OnMouseUp = FormMouseUp
  Touch.InteractiveGestures = [igPan]
  OnGesture = FormGesture
  DesignerMobile = False
  DesignerWidth = 0
  DesignerHeight = 0
  DesignerDeviceName = ''
  DesignerOrientation = 0
  DesignerOSVersion = ''
  object MainLayout: TLayout
    Align = alContents
    Height = 921.000000000000000000
    Margins.Top = 25.000000000000000000
    Width = 2600.000000000000000000
    object HorzScrollBox1: THorzScrollBox
      Align = alClient
      Height = 921.000000000000000000
      TabOrder = 0
      Width = 2600.000000000000000000
      object GroupLayout1: TLayout
        Align = alLeft
        Anchors = [akLeft, akTop]
        Height = 905.000000000000000000
        Margins.Left = 110.000000000000000000
        Position.X = 110.000000000000000000
        Width = 540.000000000000000000
        object ListBox4: TListBox
          Align = alClient
          Height = 905.000000000000000000
          StyleLookup = 'collectionlistbox'
          TabOrder = 0
          Width = 540.000000000000000000
          DefaultItemStyles.ItemStyle = ''
          DefaultItemStyles.GroupHeaderStyle = ''
          DefaultItemStyles.GroupFooterStyle = ''
        end
      end
      object GroupLayout2: TLayout
        Align = alLeft
        Anchors = [akLeft, akTop]
        Height = 905.000000000000000000
        Margins.Left = 40.000000000000000000
        Position.X = 690.000000000000000000
        Width = 1225.000000000000000000
      end
      object Layout1: TLayout
        Align = alLeft
        Anchors = [akLeft, akTop]
        Height = 905.000000000000000000
        Margins.Left = 40.000000000000000000
        Margins.Right = 100.000000000000000000
        Position.X = 1955.000000000000000000
        Width = 660.000000000000000000
        object Label1: TLabel
          Align = alTop
          AutoSize = True
          Height = 40.000000000000000000
          Margins.Left = 10.000000000000000000
          Margins.Bottom = 5.000000000000000000
          Position.X = 10.000000000000000000
          StyleLookup = 'pagesubheaderlabel'
          Text = 'Group Title: 4'
          Width = 165.000000000000000000
          WordWrap = False
        end
        object ListBox1: TListBox
          Align = alClient
          Height = 855.000000000000000000
          StyleLookup = 'collectionlistbox'
          TabOrder = 1
          Width = 660.000000000000000000
          DefaultItemStyles.ItemStyle = ''
          DefaultItemStyles.GroupHeaderStyle = ''
          DefaultItemStyles.GroupFooterStyle = ''
        end
      end
    end
  end
  object StyleBook2: TStyleBook
    Left = 632
    Top = 544
    ResourcesBin = {...}
  end
  object PrototypeBindSource1: TPrototypeBindSource
    AutoActivate = True
    AutoPost = False
    FieldDefs = <
      item
        Name = 'ContactBitmapL1'
        FieldType = ftBitmap
        Generator = 'ContactBitmapsL'
        ReadOnly = False
      end
      item
        Name = 'ContactName1'
        Generator = 'ContactNames'
        ReadOnly = False
      end
      item
        Name = 'IntField1'
        FieldType = ftInteger
        Generator = 'Integers'
        ReadOnly = False
      end>
    ScopeMappings = <>
    Left = 1288
    Top = 456
  end
  object BindingsList1: TBindingsList
    Methods = <>
    OutputConverters = <>
    Left = 20
    Top = 5
    object LinkFillControlToField1: TLinkFillControlToField
      Category = 'Quick Bindings'
      Control = ListBox4
      Track = True
      FillDataSource = PrototypeBindSource1
      FillDisplayFieldName = 'ContactName1'
      AutoFill = True
      BufferCount = -1
      AutoBufferCount = False
      ListItemStyle = 'MetropolisUI'
      FillExpressions = <
        item
          SourceMemberName = 'ContactBitmapL1'
          ControlMemberName = 'Icon'
        end
        item
          SourceMemberName = 'IntField1'
          ControlMemberName = 'SubTitle'
        end>
      FillHeaderExpressions = <>
      FillBreakGroups = <>
    end
    object LinkFillControlToField2: TLinkFillControlToField
      Category = 'Quick Bindings'
      Control = ListBox1
      Track = True
      FillDataSource = PrototypeBindSource2
      FillDisplayFieldName = 'ContactName1'
      AutoFill = True
      BufferCount = -1
      AutoBufferCount = False
      ListItemStyle = 'MetropolisUI'
      FillExpressions = <
        item
          SourceMemberName = 'FloatField1'
          ControlMemberName = 'SubTitle'
        end
        item
          SourceMemberName = 'ContactBitmap1'
          ControlMemberName = 'Icon'
        end>
      FillHeaderExpressions = <>
      FillBreakGroups = <>
    end
  end
  object PrototypeBindSource2: TPrototypeBindSource
    AutoActivate = True
    AutoPost = False
    FieldDefs = <
      item
        Name = 'ContactBitmap1'
        FieldType = ftBitmap
        Generator = 'ContactBitmaps'
        ReadOnly = False
      end
      item
        Name = 'ContactName1'
        Generator = 'ContactNames'
        ReadOnly = False
      end
      item
        Name = 'FloatField1'
        FieldType = ftSingle
        Generator = 'Floats'
        ReadOnly = False
      end>
    ScopeMappings = <>
    Left = 1232
    Top = 448
  end
end

有人对如何应对这个问题有什么建议吗？

Answer 1

我通过设置 ListBox1.CanFocus := false; 找到了答案。在某些情况下(实际上)该错误会再次出现。