我有一个与TFDMemTable绑定在一起的TListView。我也有一个TButton，将项目添加到TFDMemTable上，添加项目后，该项目显然显示在TListView中。 TListView位于TTabControl的TTabItem之一。
我的问题是，当我在运行时更改选项卡并返回到TListView选项卡以添加更多项时，先前显示的数据在添加更多项后将变为空。
我可以确认TFDMemTable中的数据仍然完整无缺，包括新添加的数据。
我怀疑需要刷新实时绑定才能将所有数据返回到TListView。
有人对如何在运行时刷新实时绑定有任何想法吗？
P.S。我希望以上内容能清楚地说明我的问题。否则，如果您需要更多详细信息，请告诉我。
更新1：最少可重复的示例
这是我对MRE所做的最少的事情，不是我所遇到的确切情况，但应该是同一问题。在TabItem2上添加列表后，您会注意到，然后回到TabItem1在列表上添加更多项，列表上的现有详细信息将消失。
FMX程序
unit TabbedFormwithNavigation;
interface
uses
System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs, FMX.TabControl, FMX.StdCtrls, FMX.Controls.Presentation,
FMX.Gestures, System.Actions, FMX.ActnList, FMX.ListView.Types,
FMX.ListView.Appearances, FMX.ListView.Adapters.Base, REST.Types,
FireDAC.Stan.Intf, FireDAC.Stan.Option, FireDAC.Stan.Param,
FireDAC.Stan.Error, FireDAC.DatS, FireDAC.Phys.Intf, FireDAC.DApt.Intf,
System.Rtti, System.Bindings.Outputs, Fmx.Bind.Editors, Data.Bind.EngExt,
Fmx.Bind.DBEngExt, Data.Bind.Components, Data.Bind.DBScope, Data.DB,
FireDAC.Comp.DataSet, FireDAC.Comp.Client, REST.Response.Adapter, REST.Client,
Data.Bind.ObjectScope, FMX.ListView;
type
TTabbedwithNavigationForm = class(TForm)
TabControl1: TTabControl;
TabItem1: TTabItem;
TabItem2: TTabItem;
GestureManager1: TGestureManager;
ActionList1: TActionList;
NextTabAction1: TNextTabAction;
PreviousTabAction1: TPreviousTabAction;
lsv1: TListView;
rsc1: TRESTClient;
rsq1: TRESTRequest;
rsp1: TRESTResponse;
rsd1: TRESTResponseDataSetAdapter;
mtb1: TFDMemTable;
bdr1: TBindSourceDB;
bdl1: TBindingsList;
lsv2: TListView;
rsc2: TRESTClient;
rsq2: TRESTRequest;
rsp2: TRESTResponse;
rsd2: TRESTResponseDataSetAdapter;
mtb2: TFDMemTable;
bdr2: TBindSourceDB;
lcf1: TLinkListControlToField;
btn1: TButton;
lsv3: TListView;
mtb3: TFDMemTable;
strngfldmtb3brandname: TStringField;
strngfldmtb3brand: TStringField;
bdr3: TBindSourceDB;
lcf3: TLinkListControlToField;
lcf2: TLinkListControlToField;
pnl1: TPanel;
lbl1: TLabel;
pnl2: TPanel;
lbl2: TLabel;
pnl3: TPanel;
lbl3: TLabel;
procedure GestureDone(Sender: TObject; const EventInfo: TGestureEventInfo; var Handled: Boolean);
procedure FormCreate(Sender: TObject);
procedure FormKeyUp(Sender: TObject; var Key: Word; var KeyChar: Char; Shift: TShiftState);
procedure lsv1ItemClick(const Sender: TObject; const AItem: TListViewItem);
procedure btn1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
TabbedwithNavigationForm: TTabbedwithNavigationForm;
implementation
{$R *.fmx}
procedure TTabbedwithNavigationForm.btn1Click(Sender: TObject);
var
brandname : string;
begin
brandname := mtb2.Lookup('name', lsv2.Items[lsv2.ItemIndex].Text, 'name');
// ShowMessage(lsv2.Items[lsv2.ItemIndex].Text);
if mtb3.Locate('brandname', brandname, []) = False then
begin
mtb3.DisableControls;
mtb3.Append;
mtb3.FieldByName('brandname').AsString := brandname;
mtb3.EnableControls;
mtb3.Post;
end;
end;
procedure TTabbedwithNavigationForm.FormCreate(Sender: TObject);
begin
{ This defines the default active tab at runtime }
TabControl1.ActiveTab := TabItem1;
rsq1.Execute;
end;
procedure TTabbedwithNavigationForm.FormKeyUp(Sender: TObject; var Key: Word; var KeyChar: Char; Shift: TShiftState);
begin
if Key = vkHardwareBack then
begin
if (TabControl1.ActiveTab = TabItem1) then
begin
Key := 0;
end;
end;
end;
procedure TTabbedwithNavigationForm.GestureDone(Sender: TObject; const EventInfo: TGestureEventInfo; var Handled: Boolean);
begin
case EventInfo.GestureID of
sgiLeft:
begin
if TabControl1.ActiveTab <> TabControl1.Tabs[TabControl1.TabCount - 1] then
TabControl1.ActiveTab := TabControl1.Tabs[TabControl1.TabIndex + 1];
Handled := True;
end;
sgiRight:
begin
if TabControl1.ActiveTab <> TabControl1.Tabs[0] then
TabControl1.ActiveTab := TabControl1.Tabs[TabControl1.TabIndex - 1];
Handled := True;
end;
end;
end;
procedure TTabbedwithNavigationForm.lsv1ItemClick(const Sender: TObject;
const AItem: TListViewItem);
var
SearchItem : String;
begin
//place the equivalent api for the meta click
SearchItem := lsv1.Items[lsv1.ItemIndex].Text;
rsc2.BaseURL := 'https://nm5c906csg.execute-api.ap-southeast-1.amazonaws.com/v0/dbqueries?search-item=' + SearchItem;
//execute api request for the searches
rsq2.Execute;
TabControl1.TabIndex := 1;
end;
end.
FMX文件
object TabbedwithNavigationForm: TTabbedwithNavigationForm
Left = 0
Top = 0
Caption = 'Form56'
ClientHeight = 596
ClientWidth = 405
FormFactor.Width = 320
FormFactor.Height = 480
FormFactor.Devices = [Desktop]
OnCreate = FormCreate
OnKeyUp = FormKeyUp
DesignerMasterStyle = 0
object TabControl1: TTabControl
Touch.GestureManager = GestureManager1
OnGesture = GestureDone
Align = Client
FullSize = True
Size.Width = 405.000000000000000000
Size.Height = 596.000000000000000000
Size.PlatformDefault = False
TabHeight = 49.000000000000000000
TabIndex = 1
TabOrder = 0
TabPosition = PlatformDefault
Sizes = (
405s
547s
405s
547s)
object TabItem1: TTabItem
CustomIcon = <
item
end>
IsSelected = False
Size.Width = 201.000000000000000000
Size.Height = 49.000000000000000000
Size.PlatformDefault = False
StyleLookup = 'tabitemfavorites'
TabOrder = 0
Text = 'TabItem1'
ExplicitSize.cx = 101.000000000000000000
ExplicitSize.cy = 49.000000000000000000
object lsv1: TListView
ItemAppearanceClassName = 'TListItemAppearance'
ItemEditAppearanceClassName = 'TListItemShowCheckAppearance'
HeaderAppearanceClassName = 'TListHeaderObjects'
FooterAppearanceClassName = 'TListHeaderObjects'
ItemIndex = 0
Align = Client
Size.Width = 405.000000000000000000
Size.Height = 487.000000000000000000
Size.PlatformDefault = False
TabOrder = 0
OnItemClick = lsv1ItemClick
end
object pnl1: TPanel
Align = Top
Size.Width = 405.000000000000000000
Size.Height = 60.000000000000000000
Size.PlatformDefault = False
TabOrder = 1
object lbl1: TLabel
Align = Client
StyledSettings = [Family, FontColor]
Margins.Left = 60.000000000000000000
Margins.Right = 60.000000000000000000
Size.Width = 285.000000000000000000
Size.Height = 60.000000000000000000
Size.PlatformDefault = False
TextSettings.Font.Size = 14.000000000000000000
TextSettings.Font.StyleExt = {00070000000000000004000000}
TextSettings.HorzAlign = Center
Text = 'Please select an item here to filter out items for TabItem2.'
TabOrder = 0
end
end
end
object TabItem2: TTabItem
CustomIcon = <
item
end>
IsSelected = True
Size.Width = 202.000000000000000000
Size.Height = 49.000000000000000000
Size.PlatformDefault = False
StyleLookup = 'tabitemcontacts'
TabOrder = 0
Text = 'TabItem2'
ExplicitSize.cx = 102.000000000000000000
ExplicitSize.cy = 49.000000000000000000
object lsv2: TListView
ItemAppearanceClassName = 'TImageListItemBottomDetailAppearance'
ItemEditAppearanceClassName = 'TImageListItemBottomDetailShowCheckAppearance'
HeaderAppearanceClassName = 'TListHeaderObjects'
FooterAppearanceClassName = 'TListHeaderObjects'
ItemIndex = 0
Align = Top
Position.Y = 60.000000000000000000
Size.Width = 405.000000000000000000
Size.Height = 221.000000000000000000
Size.PlatformDefault = False
TabOrder = 0
end
object btn1: TButton
Align = Top
StyledSettings = [Family, FontColor]
Position.Y = 281.000000000000000000
Size.Width = 405.000000000000000000
Size.Height = 40.000000000000000000
Size.PlatformDefault = False
TabOrder = 1
Text = 'SELECT'
TextSettings.Font.Size = 14.000000000000000000
TextSettings.Font.StyleExt = {00070000000000000004000000}
OnClick = btn1Click
end
object lsv3: TListView
ItemAppearanceClassName = 'TImageListItemBottomDetailAppearance'
ItemEditAppearanceClassName = 'TImageListItemBottomDetailShowCheckAppearance'
HeaderAppearanceClassName = 'TListHeaderObjects'
FooterAppearanceClassName = 'TListHeaderObjects'
Align = Client
Size.Width = 405.000000000000000000
Size.Height = 166.000000000000000000
Size.PlatformDefault = False
TabOrder = 2
end
object pnl2: TPanel
Align = Top
Size.Width = 405.000000000000000000
Size.Height = 60.000000000000000000
Size.PlatformDefault = False
TabOrder = 3
object lbl2: TLabel
Align = Client
StyledSettings = [Family, FontColor]
Margins.Left = 30.000000000000000000
Margins.Right = 30.000000000000000000
Size.Width = 345.000000000000000000
Size.Height = 60.000000000000000000
Size.PlatformDefault = False
TextSettings.Font.Size = 14.000000000000000000
TextSettings.Font.StyleExt = {00070000000000000004000000}
TextSettings.HorzAlign = Center
Text =
'Select an item below then click the "SELECT" button to list down' +
' the items selected.'
TabOrder = 0
end
end
object pnl3: TPanel
Align = Bottom
Position.Y = 487.000000000000000000
Size.Width = 405.000000000000000000
Size.Height = 60.000000000000000000
Size.PlatformDefault = False
TabOrder = 4
object lbl3: TLabel
Align = Client
StyledSettings = [Family]
Size.Width = 405.000000000000000000
Size.Height = 60.000000000000000000
Size.PlatformDefault = False
TextSettings.Font.StyleExt = {00070000000000000004000000}
TextSettings.FontColor = claRed
TextSettings.HorzAlign = Center
Text =
'The error comes when you go back to TabItem1 and select another ' +
'item, the existing details on the list will be gone.'
TabOrder = 0
end
end
end
end
object GestureManager1: TGestureManager
Sensitivity = 80.000000000000000000
Left = 48
Top = 185
GestureData = <
item
Control = TabControl1
Collection = <
item
GestureID = sgiLeft
end
item
GestureID = sgiRight
end>
end>
end
object ActionList1: TActionList
Left = 48
Top = 120
object NextTabAction1: TNextTabAction
Category = 'Tab'
end
object PreviousTabAction1: TPreviousTabAction
Category = 'Tab'
end
end
object rsc1: TRESTClient
Accept = 'application/json, text/plain; q=0.9, text/html;q=0.8,'
AcceptCharset = 'utf-8, *;q=0.8'
BaseURL =
'https://bs3winlz02.execute-api.ap-southeast-1.amazonaws.com/v0/d' +
'bqueries'
Params = <>
Left = 136
Top = 120
end
object rsq1: TRESTRequest
Client = rsc1
Params = <>
Response = rsp1
SynchronizedEvents = False
Left = 136
Top = 184
end
object rsp1: TRESTResponse
ContentType = 'application/json'
Left = 136
Top = 248
end
object rsd1: TRESTResponseDataSetAdapter
Active = True
Dataset = mtb1
FieldDefs = <>
Response = rsp1
Left = 136
Top = 312
end
object mtb1: TFDMemTable
Active = True
FieldDefs = <
item
Name = 'meta'
DataType = ftWideString
Size = 255
end>
IndexDefs = <>
FetchOptions.AssignedValues = [evMode]
FetchOptions.Mode = fmAll
ResourceOptions.AssignedValues = [rvSilentMode]
ResourceOptions.SilentMode = True
UpdateOptions.AssignedValues = [uvCheckRequired, uvAutoCommitUpdates]
UpdateOptions.CheckRequired = False
UpdateOptions.AutoCommitUpdates = True
StoreDefs = True
Left = 136
Top = 376
end
object bdr1: TBindSourceDB
DataSet = mtb1
ScopeMappings = <>
Left = 136
Top = 440
end
object bdl1: TBindingsList
Methods = <>
OutputConverters = <>
Left = 20
Top = 5
object lcf1: TLinkListControlToField
Category = 'Quick Bindings'
DataSource = bdr1
FieldName = 'meta'
Control = lsv1
FillExpressions = <>
FillHeaderExpressions = <>
FillBreakGroups = <>
end
object lcf3: TLinkListControlToField
Category = 'Quick Bindings'
DataSource = bdr3
FieldName = 'brandname'
Control = lsv3
FillExpressions = <
item
SourceMemberName = 'brand'
ControlMemberName = 'Detail'
end>
FillHeaderExpressions = <>
FillBreakGroups = <>
end
object lcf2: TLinkListControlToField
Category = 'Quick Bindings'
DataSource = bdr2
FieldName = 'name'
Control = lsv2
FillExpressions = <
item
SourceMemberName = 'brand'
ControlMemberName = 'Detail'
end>
FillHeaderExpressions = <>
FillBreakGroups = <>
end
end
object rsc2: TRESTClient
Accept = 'application/json, text/plain; q=0.9, text/html;q=0.8,'
AcceptCharset = 'utf-8, *;q=0.8'
BaseURL =
'https://nm5c906csg.execute-api.ap-southeast-1.amazonaws.com/v0/d' +
'bqueries?search-item=sage'
Params = <>
Left = 200
Top = 120
end
object rsq2: TRESTRequest
Client = rsc2
Params = <>
Response = rsp2
SynchronizedEvents = False
Left = 200
Top = 184
end
object rsp2: TRESTResponse
ContentType = 'application/json'
Left = 200
Top = 248
end
object rsd2: TRESTResponseDataSetAdapter
Active = True
Dataset = mtb2
FieldDefs = <>
Response = rsp2
Left = 200
Top = 312
end
object mtb2: TFDMemTable
Active = True
FieldDefs = <
item
Name = 'brand'
DataType = ftWideString
Size = 255
end
item
Name = 'name'
DataType = ftWideString
Size = 255
end
item
Name = 'description'
DataType = ftWideString
Size = 255
end>
IndexDefs = <>
FetchOptions.AssignedValues = [evMode]
FetchOptions.Mode = fmAll
ResourceOptions.AssignedValues = [rvSilentMode]
ResourceOptions.SilentMode = True
UpdateOptions.AssignedValues = [uvCheckRequired, uvAutoCommitUpdates]
UpdateOptions.CheckRequired = False
UpdateOptions.AutoCommitUpdates = True
StoreDefs = True
Left = 200
Top = 376
end
object bdr2: TBindSourceDB
DataSet = mtb2
ScopeMappings = <>
Left = 200
Top = 440
end
object mtb3: TFDMemTable
Active = True
FetchOptions.AssignedValues = [evMode]
FetchOptions.Mode = fmAll
ResourceOptions.AssignedValues = [rvSilentMode]
ResourceOptions.SilentMode = True
UpdateOptions.AssignedValues = [uvCheckRequired, uvAutoCommitUpdates]
UpdateOptions.CheckRequired = False
UpdateOptions.AutoCommitUpdates = True
Left = 264
Top = 376
object strngfldmtb3brandname: TStringField
FieldName = 'brandname'
Size = 200
end
object strngfldmtb3brand: TStringField
FieldKind = fkLookup
FieldName = 'brand'
LookupDataSet = mtb2
LookupKeyFields = 'name'
LookupResultField = 'brand'
KeyFields = 'brandname'
Size = 200
Lookup = True
end
end
object bdr3: TBindSourceDB
DataSet = mtb3
ScopeMappings = <>
Left = 264
Top = 440
end
end
答案 0 :(得分：1)
错误在于我在FDMemTable（mtb3）中创建的Lookup字段。我避免了这些。相反，我创建了一个普通数据字段，并直接从TListView（lsv2）中获取数据，如下所示：
FMX程序
procedure TTabbedwithNavigationForm.btn1Click(Sender: TObject);
var
brandname, brand : string;
begin
brandname := mtb2.Lookup('name', lsv2.Items[lsv2.ItemIndex].Text, 'name');
brand := mtb2.Lookup('name', lsv2.Items[lsv2.ItemIndex].Text, 'brand');
if mtb3.Locate('brandname', brandname, []) = False then
begin
mtb3.DisableControls;
mtb3.Append;
mtb3.FieldByName('brandname').AsString := brandname;
mtb3.FieldByName('brand').AsString := brand; //manually coded instead of lookup field in the fdmemtable (mtb3)
mtb3.EnableControls;
mtb3.Post;
end;
end;
FMX文件
object mtb3: TFDMemTable
Active = True
FieldDefs = <
item
Name = 'brandname'
DataType = ftString
Size = 200
end
item
Name = 'brand'
DataType = ftString // defined as data instead of lookup
Size = 100
end>
IndexDefs = <>
FetchOptions.AssignedValues = [evMode]
FetchOptions.Mode = fmAll
ResourceOptions.AssignedValues = [rvSilentMode]
ResourceOptions.SilentMode = True
UpdateOptions.AssignedValues = [uvCheckRequired, uvAutoCommitUpdates]
UpdateOptions.CheckRequired = False
UpdateOptions.AutoCommitUpdates = True
StoreDefs = True
Left = 264
Top = 376
object strngfldmtb3brandname: TStringField
FieldName = 'brandname'
Size = 200
end
object strngfldmtb3brand: TStringField
FieldName = 'brand'
Size = 100
end
end