4

在上一个问题中，我询问了有关在网格面板中拖放的问题。

在 GridPanel 中拖放 N 个控件

我接下来要问的问题是，当我尝试在其他控件附近对角移动控件时，我的行为很奇怪。不应该移动的控件正在移动单元格。上下左右都可以。但是对角线移动，当移动的单元格内容与其他持有控件的单元格位于同一行/列时，将导致意外的移动。我已经尝试了 beginupdate/endupdate 的转变仍然发生。网格面板有一个 LOCK 功能，但可以锁定任何东西。当放置在一个空单元格上时会发生这种情况，甚至是已经有内容的单元格。

这是测试项目（Delphi 2010 w/o exe） http://www.mediafire.com/?xmrgm7ydhygfw2r

type
  TForm1 = class(TForm)
    GridPanel1: TGridPanel;
    btn1: TButton;
    btn3: TButton;
    btn2: TButton;
    lbl1: TLabel;
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
    procedure GridPanelDragDrop(Sender, Source: TObject; X, Y: Integer);
    procedure btnDragOver(Sender, Source: TObject; X, Y: Integer;
      State: TDragState; var Accept: Boolean);
    procedure btnDragDrop(Sender, Source: TObject; X, Y: Integer);
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure SetColumnWidths(aGridPanel: TGridPanel);
var
  i,pct: Integer;
begin
  aGridPanel.ColumnCollection.BeginUpdate;
  pct:=Round(aGridPanel.ColumnCollection.Count/100);
  for i := 0 to aGridPanel.ColumnCollection.Count - 1 do begin
    aGridPanel.ColumnCollection[i].SizeStyle := ssPercent;
    aGridPanel.ColumnCollection[i].Value     := pct;
  end;
  aGridPanel.ColumnCollection.EndUpdate;
end;

procedure SetRowWidths(aGridPanel: TGridPanel);
var
  i,pct: Integer;
begin
  aGridPanel.RowCollection.BeginUpdate;
  pct:=Round(aGridPanel.RowCollection.Count/100);
  for i := 0 to aGridPanel.RowCollection.Count - 1 do begin
    aGridPanel.RowCollection[i].SizeStyle := ssPercent;
    aGridPanel.RowCollection[i].Value     := pct;
  end;
  aGridPanel.RowCollection.EndUpdate;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  btn1.OnDragOver := btnDragOver;
  btn2.OnDragOver := btnDragOver;
  btn3.OnDragOver := btnDragOver;
  GridPanel1.OnDragOver := btnDragOver;
  GridPanel1.OnDragDrop := GridPanelDragDrop;

  btn1.OnDragDrop := btnDragDrop;
  btn2.OnDragDrop := btnDragDrop;
  btn3.OnDragDrop := btnDragDrop;

  SetColumnWidths(GridPanel1);
  SetRowWidths(GridPanel1);
end;

procedure TForm1.btnDragOver(Sender, Source: TObject; X, Y: Integer;
  State: TDragState; var Accept: Boolean);
begin
  Accept := (Source is TButton);
end;

procedure TForm1.btnDragDrop(Sender, Source: TObject; X, Y: Integer);
var
  src_x,src_y, dest_x, dest_y: Integer;
  btnNameSrc,btnNameDest: string;
  src_ctrlindex,dest_ctrlindex:integer;
begin
  if Source IS tBUTTON then
  begin
    //GridPanel1.ColumnCollection.BeginUpdate;
    btnNameSrc := (Source as TButton).Name;
    btnNameDest := (Sender as TButton).Name;
    src_ctrlindex := GridPanel1.ControlCollection.IndexOf(Source as tbutton);
    src_x := GridPanel1.ControlCollection.Items[src_ctrlindex].Column;
    src_y := GridPanel1.ControlCollection.Items[src_ctrlindex].Row;

    dest_ctrlindex := GridPanel1.ControlCollection.IndexOf(Sender as tbutton);
    dest_x := GridPanel1.ControlCollection.Items[dest_ctrlindex].Column;
    dest_y := GridPanel1.ControlCollection.Items[dest_ctrlindex].Row;

    GridPanel1.ControlCollection[src_ctrlindex].Column := dest_x;
    GridPanel1.ControlCollection[src_ctrlindex].Row := dest_y;
    //GridPanel1.ColumnCollection.EndUpdate;

    lbl1.Caption := Format('"%s" from cell %d:%d to Cell %s=%d:%d', [btnNameSrc,src_x,src_y,btnNameDest,dest_x,dest_y]);

  end;
end;

procedure TForm1.GridPanelDragDrop(Sender, Source: TObject; X, Y: Integer);
var
  DropPoint: TPoint;
  CellRect: TRect;
  i_col, i_row, src_x,src_y, dest_x, dest_y: Integer;
  btnNameSrc,btnNameDest: string;
  src_ctrlindex:integer;
begin
  if Source is tbutton then
  begin
    btnNameSrc := (Source as TButton).Name;
    btnNameDest := '';
    src_ctrlindex := GridPanel1.ControlCollection.IndexOf(Source as tbutton);
    src_x := GridPanel1.ControlCollection.Items[src_ctrlindex].Column;
    src_y := GridPanel1.ControlCollection.Items[src_ctrlindex].Row;

    DropPoint := Point(X, Y);
    for i_col := 0 to GridPanel1.ColumnCollection.Count-1 do
      for i_row := 0 to GridPanel1.RowCollection.Count-1 do
      begin
        CellRect := GridPanel1.CellRect[i_col, i_row];
        if PtInRect(CellRect, DropPoint) then
        begin
          // Button was dropped over Cell[i_col, i_row]
          dest_x := i_col;
          dest_y := i_row;
          Break;
        end;
      end;
    lbl1.Caption := Format('"%s" from cell %d:%d to Cell %s=%d:%d', [btnNameSrc,src_x,src_y,btnNameDest,dest_x,dest_y]);

    GridPanel1.ControlCollection[src_ctrlindex].Column := dest_x;
    GridPanel1.ControlCollection[src_ctrlindex].Row := dest_y;
  end;
end;
4

3 回答 3

4

这与拖动无关，当项目的列和行都在更改时，更改分两步进行。使用您的代码，首先是列，然后是行。如果在列变化fi中，恰好已经有另一个控件，这个另一个控件被推到一边，即使它的单元格不是移动控件的目标单元格的最终位置。

Begin/EndUpdate 将不起作用，控制集合从不检查更新计数。你能做的是使用受保护的黑客来访问控制项的InternalSetLocation方法。此方法有一个“MoveExisting”参数，您可以传递“False”。

type
  THackControlItem = class(TControlItem);

procedure TForm1.GridPanelDragDrop(Sender, Source: TObject; X, Y: Integer);
var
  [...]
begin
  if Source is tbutton then
  begin

    [...]

    lbl1.Caption := Format('"%s" from cell %d:%d to Cell %s=%d:%d', [btnNameSrc,src_x,src_y,btnNameDest,dest_x,dest_y]);

    THackControlItem(GridPanel1.ControlCollection[src_ctrlindex]).
        InternalSetLocation(dest_x, dest_y, False, False);
//    GridPanel1.ControlCollection[src_ctrlindex].Column := dest_x;
//    GridPanel1.ControlCollection[src_ctrlindex].Row := dest_y;
  end;
end;

您可能需要在调用“InternalSetLocation”之前测试目标单元格是否为空，具体取决于您期望的正确控制运动。

于 2011-03-20T16:40:52.460 回答
1

我使用一种完全不同的方式来完成工作......创建一个完整的单元只是为了在ExtCtrls.TControlCollection不接触单元的情况下添加一个方法ExtCtrls（第一次破解）并使用这种方法 InternalSetLocation（第二次破解）。我还在这篇文章中解释了这两种技巧。

然后我只需要将这样的单元添加到实现使用部分（在网格面板声明之前）并调用我创建的方法......非常易于使用。

这是我如何做的，一步一步：

  1. 我将我为此类工作制作的此类单元包含到项目中（添加文件）
  2. 我添加到我的 TForm 界面使用部分这样的单元（或我需要它的地方）
  3. 我用我的方法AddControlAtCell代替ExtCtrls.TControlCollection.AddControl

这是我为此类工作创建的单元，将其另存为unitTGridPanel_WithAddControlAtCell：

unit unitTGridPanel_WithAddControlAtCell;

interface

uses
    Controls
   ,ExtCtrls
   ;

type TGridPanel=class(ExtCtrls.TGridPanel)
   private
   public
     procedure AddControlAtCell(AControl:TControl;AColumn:Integer;ARow:Integer); // Add Control on specifed cell, if there already exists a Control it will be deleted
 end;

implementation

uses
    SysUtils
   ;

type
    THackControlItem=class(TControlItem); // To get internal access to InternalSetLocation procedure
procedure TGridPanel.AddControlAtCell(AControl:TControl;AColumn:Integer;ARow:Integer);
var
   TheControlItem:TControlItem; // To let it be added in a specified cell, since ExtCtrls.TControlCollection.AddControl contains multiply BUGs
begin // Add Control on specifed cell, if there already exists a Control it will be deleted
     if   (-1<AColumn)and(AColumn<ColumnCollection.Count) // Cell with valid Column
       and // Cell inside valid range
          (-1<ARow)and(ARow<RowCollection.Count) // Cell with valid Row
     then begin // Valid cell, must check if there is already a control
               if   (Nil<>ControlCollection.ControlItems[AColumn,ARow]) // Check if there are any controls
                 and // A control is already on the cell
                    (Nil<>ControlCollection.ControlItems[AColumn,ARow].Control) // Check if cell has a control
               then begin // There is already a control, must be deleted
                         ControlCollection.Delete(ControlCollection.IndexOf(ControlCollection.ControlItems[AColumn,ARow].Control)); // Delete the control
                    end;
               TheControlItem:=ControlCollection.Add; // Create the TControlItem
               TheControlItem.Control:=TControl(AControl); // Put the Control in the specified cell without altering any other cell
               THackControlItem(ControlCollection.Items[ControlCollection.IndexOf(AControl)]).InternalSetLocation(AColumn,ARow,False,False); // Put the ControlItem in the cell without altering any other cell
          end
     else begin // Cell is out of range
               raise Exception.CreateFmt('Cell [%d,%d] out of range on ''%s''.',[AColumn,ARow,Name]);
          end;
end;

end.

我希望评论足够清楚，请阅读它们以了解我为什么以及如何这样做。

然后，当我需要在指定单元格的网格面板中添加控件时，我执行下一个简单调用：

TheGridPanel.AddControlAtCell(TheControl,ACloumn,ARow); // Add it at desired cell without affecting other cells

在特定单元格添加运行时新创建的 TCheckBox 的一个非常非常基本的示例可能是这样的：

// AColumn      is of Type Integer
// ARow         is of Type Integer
// ACheckBox    is of Type TCheckBox
// TheGridPanel is of Type TGridPanel
ACheckBox:=TCheckBox.Create(TheGridPanel); // Create the Control to be added (a CheckBox)
ACheckBox.Visible:=False; // Set it to not visible, for now (optimization on speed, e tc)
ACheckBox.Color:=TheGridPanel.Color; // Just to use same background as on the gridpanel
ACheckBox.Parent:=TheGridPanel; // Set the parent of the control as the gridpanel (mandatory)
TheGridPanel.AddControlAtCell(ElCheckBox,ACloumn,ARow); // Add it at desired cell without affecting other cells
ElCheckBox.Visible:=True; // Now it is added, make it visible
ElCheckBox.Enabled:=True; // And of course, ensure it is enabled if needed

请注意，我使用这两个黑客：

  1. type THackControlItem让我访问该方法InternalSetLocation。
  2. type TGridPanel=class(ExtCtrls.TGridPanel)让我添加一个方法，ExtCtrls.TGridPanel甚至无需触摸（不需要的来源ExtCtrls）

重要提示：还请注意，我提到它需要将单元添加到您要使用该方法的每个表单的界面的使用中AddControlAtCell；那是针对普通人的，高级人员也可以创建另一个单元，等等...“概念”是在声明您要使用它的 GridPanel 之前使用该单元...例如：如果 GridPanel 是在设计时放在表单上......它必须继续使用这种表单单元。

希望这对其他人有帮助。

于 2013-07-09T09:06:04.660 回答
0

下面的解决方案无需任何黑客攻击即可工作。

我的代码在 C++ Builder 中，但我认为它只是为了让 Delphi 用户理解，因为它只依赖于 VCL 函数。PS：请注意，我拖动 TPanels 而不是 TButtons（一个非常小的变化）。 

void TfrmVCL::ButtonDragDrop(TObject *Sender, TObject *Source, int X, int Y)
{
  TRect CurCellRect;
  TRect DestCellRect;
  int Col;
  int Row;
  int destCol; int destRow;
  int srcIndex; int destIndex;
  TPanel *SrcBtn;
  TPanel *DestBtn;

  SrcBtn = dynamic_cast<TPanel *>(Source);
  if (SrcBtn)
     {
     int ColCount = GridPnl->ColumnCollection->Count ;
     int RowCount = GridPnl->RowCollection->Count ;

     // SOURCE
     srcIndex = GridPnl->ControlCollection->IndexOf( SrcBtn );

     // DESTINATION
     // we get coordinates of the button I drag onto
     DestBtn= dynamic_cast<TPanel *>(Sender);
     if (!DestBtn) return;
     destIndex    = GridPnl->ControlCollection->IndexOf( DestBtn );
     destCol      = GridPnl->ControlCollection->Items[ destIndex ]->Column;  // the column for the dragged button
     destRow      = GridPnl->ControlCollection->Items[ destIndex ]->Row;
     DestCellRect = GridPnl->CellRect[ destCol ][ destRow ];

     // Check all cells
     for ( Col = 0 ; Col < ColCount ; Col++ )
        {
        for ( Row = 0 ; Row < RowCount ; Row++ )
           {
             // Get the bounding rect for this cell
             CurCellRect = GridPnl->CellRect[ Col ][ Row ];

             if (IntersectRect_ForReal(DestCellRect, CurCellRect))
                {
                GridPnl->ControlCollection->Items[srcIndex]->SetLocation(Col, Row, false);
                return;
                }
           }
        }
     }
}
于 2018-11-21T14:51:06.397 回答