delphi中TDBGrid的使用 c 句柄 tdbgrid

2010-06-24 10:03

procedure TMainForm.DBGrid1DrawColumnCell(Sender: TObject;

const Rect: TRect; DataCol: Integer; Column: TColumn;State: TGridDrawState);

var i :integer;

begin

if gdSelected in State then Exit;

//定义表头的字体和背景颜色:

for i :=0 to (Sender as TDBGrid).Columns.Count-1 do

begin

(Sender as TDBGrid).Columns[i].Title.Font.Name :='宋体'; //字体

(Sender as TDBGrid).Columns[i].Title.Font.Size :=9; //字体大小

(Sender as TDBGrid).Columns[i].Title.Font.Color :=$000000ff; //字体颜色(红色)

(Sender as TDBGrid).Columns[i].Title.Color :=$0000ff00; //背景色(绿色)

end;

//隔行改变网格背景色:

if Query1.RecNo mod 2 = 0 then

(Sender as TDBGrid).Canvas.Brush.Color := clInfoBk //定义背景颜色

else

(Sender as TDBGrid).Canvas.Brush.Color := RGB(191, 255, 223); //定义背景颜色

//定义网格线的颜色:

DBGrid1.DefaultDrawColumnCell(Rect,DataCol,Column,State);

with (Sender as TDBGrid).Canvas do //画 cell 的边框

begin

Pen.Color := $00ff0000; //定义画笔颜色(蓝色)

MoveTo(Rect.Left, Rect.Bottom); //画笔定位

LineTo(Rect.Right, Rect.Bottom); //画蓝色的横线

Pen.Color := $0000ff00; //定义画笔颜色(绿色)

MoveTo(Rect.Right, Rect.Top); //画笔定位

LineTo(Rect.Right, Rect.Bottom); //画绿色的竖线

end;

end;

-----------------------------------------------

procedure TForm1.DBGrid1DrawDataCell(Sender: TObject; const Rect: TRect; Field: TField; State: TGridDrawState);

begin

if (gdFocused in State) then

begin

if (Field.FieldName = DBComboBox1.DataField ) then

begin

DBComboBox1.Left := Rect.Left + DBGrid1.Left;

DBComboBox1.Top := Rect.Top + DBGrid1.top;

DBComboBox1.Width := Rect.Right - Rect.Left;

DBComboBox1.Height := Rect.Bottom - Rect.Top;

DBComboBox1.Visible := True;

end;

end;

end;

-----------------------------------------------

procedure TForm1.DBGrid1ColExit(Sender: TObject);

begin

If DBGrid1.SelectedField.FieldName = DBComboBox1.DataField then

begin

DBComboBox1.Visible := false;

end;

end;

-----------------------------------------------

在DbGrid的DrawColumnCell事件中编写如下代码:

Case DataCol Mod 2 = 0 of

True: DbGrid1.Canvas.Brush.Color:= clBlue; file://偶数列用蓝色

False: DbGrid1.Canvas.Brush.Color:= clAqua; file://奇数列用浅绿色

End;

DbGrid1.Canvas.Pen.Mode:=pmMask;

DbGrid1.DefaultDrawColumnCell (Rect

DataCol

Column

State);

-----------------------------------------------

Case DataCol Mod 2 = 0 of

True: DbGrid1.Canvas.Brush.Color:= clBlue; file://偶数列用蓝色

False: DbGrid1.Canvas.Brush.Color:= clAqua; file://奇数列用浅绿色

End;

If ((State = [gdSelected]) or (State=[gdSelectedgdFocused])) then

If Not DbGrid1.SelectedRows.CurrentRowSelected then

DbGrid1.Canvas.Brush.Color:=clRed; file://当前选中单元格显示红色

DbGrid1.Canvas.Pen.Mode:=pmMask;

DbGrid1.DefaultDrawColumnCell (Rect

DataCol

Column

State);

-----------------------------------------------

设置DbGrid控件的Options属性中的dgRowSelect属性为真,Color属性为clAqua(背景色)

在DbGrid的DrawColumnCell事件中编写如下代码:

if ((State = [gdSelected]) or (State=[gdSelected gdFocused])) then

DbGrid1.Canvas.Brush.color:=clRed; file://当前行以红色显示,其它行使用背景的浅绿色

DbGrid1.Canvas.pen.mode:=pmmask;

DbGrid1.DefaultDrawColumnCell (Rect

DataCol

Column

State);

-----------------------------------------------

if ((State = [gdSelected]) or (State=[gdSelectedgdFocused])) then

begin

Case DataCol Mod 2 = 0 of

True : DbGrid1.Canvas.Brush.color:=clRed; file://当前选中行的偶数列显示红色

False: DbGrid1.Canvas.Brush.color:=clblue; file://当前选中行的奇数列显示蓝色

end;

DbGrid1.Canvas.pen.mode:=pmmask;

DbGrid1.DefaultDrawColumnCell (Rect

DataCol

Column

State);

end;

-----------------------------------------------

横向斑马线, 同时以红色突显当前行效果。

file://其它属性设置同3,将上述代码修改为:

Case Table1.RecNo mod 2 = 0 of file://根据数据集的记录号进行判断

True : DbGrid1.Canvas.Brush.color:=clAqua; file://偶数行用浅绿色显示

False: DbGrid1.Canvas.Brush.color:=clblue; file://奇数行用蓝色表示

end;

if ((State = [gdSelected]) or (State=[gdSelectedgdFocused])) then file://选中行用红色显示

DbGrid1.Canvas.Brush.color:=clRed;

DbGrid1.Canvas.pen.mode:=pmMask;

DbGrid1.DefaultDrawColumnCell (Rect

DataCol

Column

State);

-----------------------------------------------

双向斑马线效果:即行间用不同色区分,同时,选中行以纵向斑马线效果区分不同的列。

file://其它属性设置同3,将上述代码修改为:

Case Table1.RecNo mod 2 = 0 of file://根据数据集的记录号进行判断

True : DbGrid1.Canvas.Brush.color:=clAqua; file://偶数行用浅绿色显示

False: DbGrid1.Canvas.Brush.color:= clblue; file://奇数行用蓝色表示

end;

If ((State = [gdSelected]) or (State=[gdSelectedgdFocused])) then

Case DataCol mod 2 = 0 of

True : DbGrid1.Canvas.Brush.color:=clRed; file://当前选中行的偶数列用红色

False: DbGrid1.Canvas.Brush.color:= clGreen; file://当前选中行的奇数列用绿色表示

end;

DbGrid1.Canvas.pen.mode:=pmMask;

DbGrid1.DefaultDrawColumnCell (Rect

DataCol

Column

State);

-----------------------------------------------

DBGrid不支持鼠标的上下移动的解决代码(感谢 wangxian11 提供)自己捕捉WM_MOUSEWHEEL消息处理

private

OldGridWnd : TWndMethod;

procedure NewGridWnd (var Message : TMessage);

public

procedure TForm1.NewGridWnd(var Message: TMessage);

var

IsNeg : Boolean;

begin

if Message.Msg = WM_MOUSEWHEEL then

begin

IsNeg := Short(Message.WParamHi) < 0;

if IsNeg then

DBGrid1.DataSource.DataSet.MoveBy(1)

else

DBGrid1.DataSource.DataSet.MoveBy(-1)

end

else

OldGridWnd(Message);

end;

procedure TForm1.FormCreate(Sender: TObject);

begin

OldGridWnd := DBGrid1.WindowProc ;

DBGrid1.WindowProc := NewGridWnd;

end;

-----------------------------------------------

dbgrid中移动焦点到指定的行和列 dbgrid是从TCustomGrid继承下来的,它有col与row属性,只不过是protected的,不能直接访问,要处理一下,可以这样:

Query1.first;

TDrawGrid(dbgrid1).col:=1;

dbgrid1.setfocus;

-----------------------------------------------

procedure TForm1.DBGrid1DrawDataCell(Sender: TObject; const Rect: TRect;Field: TField; State: TGridDrawState);

begin

if Table1.Fieldbyname(′Salary′).value<=SpinEdit1.value then

DBGrid1.Canvas.Brush.Color:=ColorGrid1.ForeGroundColor

else

DBGrid1.Canvas.Brush.Color:=ColorGrid1.BackGroundColor;

DBGrid1.Canvas.FillRect(Rect);

DBGrid1.Canvas.TextOut(Rect.left+2,Rect.top+2,Field.AsString);

end;

-----------------------------------------------

1.为SpinEdit1构件的OnChange事件编写响应代码:

procedure TForm1.SpinEdit1Change(Sender: TObject);

begin

DBGrid1.refresh; //刷新是必须的

end;

当SpinEdit1构件的值有所改变时,重新刷新DBGrid1。

2.为ColorGrid1的OnChange事件编写响应代码:

procedure TForm1.ColorGrid1Change(Sender: TObject);

begin

DBGrid1.refresh; //刷新是必须的

end;

当ColorGrid1的值有所改变时,即鼠标的右键或左键单击ColorGrid1重新刷新DBGrid1。

3.为Form1窗体(主窗体)的OnCreate事件编写响应代码:

procedure TForm1.FormCreate(Sender: TObject);

begin

ColorGrid1.ForeGroundIndex:=9;

ColorGrid1.BackGroundIndex:=15;

end;

-----------------------------------------------

判断Grid是否有滚动条?

if (GetWindowlong(Stringgrid1.Handle, GWL_STYLE) and WS_VSCROLL) <> 0 then

ShowMessage('Vertical scrollbar is visible!');

if (GetWindowlong(Stringgrid1.Handle, GWL_STYLE) and WS_HSCROLL) <> 0 then

ShowMessage('Horizontal scrollbar is visible!');

-----------------------------------------------

1、 数据表的建立

在Delphi的工具菜单中选择Database desktop,在数据库DBDemos下建立一个名为

example.db的数据表。数据表的字段和内容如下:

Name Age Wage

张山 25 500

王武 57 1060

李市 30 520

刘牛 28 390

2、创建基于TDBGrid的TColoredDBGrid组件

在Delphi组件菜单中,选择New Component,在弹出对话框中作以下设置:

Ancestor Type = TDBGrid

Class Name = TColoredDBGrid

然后单击OK按钮,Delphi自动完成组件基本框架的定义。增添OnDRawColoredDBGrid事件并

使它出现在Object Inspector的Events中以便在应用程序中设定改变行颜色的条件。重载

DrawCell方法,只能自己绘制单元格。不能通过在OnDrawColumnCell来设置颜色,因为在

OnDrawColumnCell改变单元格的颜色会再次触发OnDrawColumnCell。

下面就是所创建组件的源程序 。

3、建立应用程序进行验证。

在Delphi文件菜单中选择New建立新的应用程序工程Project1和主窗体Form1,设置Form1的

Caption属性为“控制DBGrid行颜色的示例”。在主窗体上添加Data Source、Table、Button和

ColoredDBGrid组件。设置各组件的属性如下:

Table1.Database=’DBDemos’

Table1.Tablename=’example.db’

Datasource1.Dataset=Table1

ColoredDBGrid1.Datasource=DataSource1

Button1.Caption=’退出’

在ColoredDBGrid1的onDRawColoredDBGrid事件中输入下列代码,设定由Wage(工资)来决

定在ColoredDBGrid1各行的颜色。

procedure TForm1.ColoredDBGrid1 DRawColoredDBGrid (Sender: TObject; Field: TField; var Color: TColor; var Font: TFont);

Var

p : Integer;

begin

p := Table1.FindField('wage').AsInteger;

//取得当前记录的Wage字段的值。

if (p < 500) then begin

//程序将根据wage值设置各行的颜色。

Color := clGreen;

Font.Style := [fsItalic];

//不仅可以改变颜色,还可以改变字体

end;

if(p >= 500) And (p < 800) then

Color := clRed;

if(p >=800) then begin

Color := clMaroon;

Font.Style := [fsBold];

end;

end;

-----------------------------------------------

unit NewDBGrid;

interface

uses

Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, DB, Grids, DBGrids, Excel97;

type

TDrawFieldCellEvent = procedure(Sender: TObject; Field: TField;

var Color: TCOlor; var Font: TFont; Row: Longint) of object;

//新的数据控件由 TDBGrid 继承而来

TNewDBGrid = class(TDBGrid)

private

//私有变量

FWZebra: Boolean; //是否显示斑马颜色

FWFirstColor: TColor; //单数行颜色

FWSecondColor: TCOlor; //双数行颜色

FDrawFieldCellEvent: TDrawFieldCellEvent;

procedure AutoInitialize; //自动初使化过程

procedure AutoDestroy;

function GetWFirstColor: TColor;

//FirstColor 的读写函数及过程

procedure SetWFirstColor(Value: TColor);

function GetWSecondColor: TCOlor;

procedure SetWSecondColor(Value: TColor);

function GetWZebra: Boolean;

procedure SetWZebra(Value: Boolean);

protected

procedure Scroll(Distance: Integer); override;

//本控件的重点过程

procedure DrawCell(Acol, ARow: Longint; ARect:

TRect; AState: TGridDrawState); override;

public

constructor Create(AOwner: TComponent); override;

destructor Destroy; override;

published

property WZebra: Boolean read GetWZebra write SetWZebra;

property OnDblClick;

property OnDragDrop;

property OnKeyUp;

property OnKeyDown;

property OnKeyPress;

property OnEnter;

property OnExit;

property OnDrawDataCell;

property WFirstColor: TColor

read GetWFirstColor write SetWFirstColor;

property WSecondColor: TColor

read GetWSecondColor write SetWSecondColor;

end;

procedure Register;

implementation

procedure Register;

begin

RegisterComponents('Data Controls', [TNewDBGrid]);

end;

procedure TNewDBGrid.AutoInitialize;

begin

FWFirstColor := RGB(239, 254, 247);

FWSecondColor := RGB(249, 244, 245);

{可以在次添加需要的其它控件及初使化参数}

end;

procedure TNewDBGrid.AutoDestroy;

begin

{在这里释放自己添加参数等占用的系统资源}

end;

procedure TNewDBGrid.SetWZebra(Value: Boolean);

begin

FWZebra := Value;

Refresh;

end;

function TNewDBGrid.GetWZebra: Boolean;

begin

Result := FWZebra;

end;

function TNewDBGrid.GetWFirstColor: TColor;

begin

Result := FWFirstColor;

end;

procedure TNewDBGrid.SetWFirstColor(Value: TColor);

begin

FWFirstColor := Value;

Refresh;

end;

function TNewDBGrid.GetWSecondColor: TColor;

begin

Result := FWSecondColor;

end;

procedure TNewDBGrid.SetWSecondColor(Value: TColor);

begin

FWSecondColor := Value;

Refresh;

end;

constructor TNewDBGrid.Create(AOwner: TComponent);

begin

inherited Create(AOwner);

AutoInitialize;

end;

destructor TNewDBGrid.Destroy;

begin

AutoDestroy;

inherited Destroy;

end;

//实现斑马效果

procedure TNewDBGrid.DrawCell(ACol, ARow:

Longint; ARect: TRect; AState: TGridDrawState);

var

OldActive: Integer;

Highlight: Boolean;

Value: string;

DrawColumn: Tcolumn;

cl: TColor;

fn: TFont;

begin

{如果处于控件装载状态,则直接填充颜色后退出}

if csLoading in ComponentState then

begin

Canvas.Brush.Color := Color;

Canvas.FillRect(ARect);

Exit;

end;

if (gdFixed in AState) and (ACol - IndicatorOffset < 0) then

begin

inherited DrawCell(ACol, ARow, ARect, AState);

Exit;

end;

{对于列标题,不用任何修饰}

if (dgTitles in Options) and (ARow = 0) then

begin

inherited DrawCell(ACol, ARow, ARect, AState);

Exit;

end;

if (dgTitles in Options) then Dec(ARow);

Dec(ACol, IndicatorOffset);

if (gdFixed in AState) and ([dgRowLines, dgColLines] * Options =

[dgRowLines, dgColLines]) then

begin

{缩减ARect,以便填写数据}

InflateRect(ARect, -1, -1);

end

else

with Canvas do

begin

DrawColumn := Columns[ACol];

Font := DrawColumn.Font;

Brush.Color := DrawColumn.Color;

Font.Color := DrawColumn.Font.Color;

if FWZebra then //如果属性WZebra为True则显示斑马纹

if Odd(ARow) then

Brush.Color := FWSecondColor

else

Brush.Color := FWFirstColor;

if (DataLink = nil) or not DataLink.Active then

FillRect(ARect)

else

begin

Value := '';

OldActive := DataLink.ActiveRecord;

try

DataLink.ActiveRecord := ARow;

if Assigned(DrawColumn.Field) then

begin

Value := DrawColumn.Field.DisplayText;

if Assigned(FDrawFieldCellEvent) then

begin

cl := Brush.Color;

fn := Font;

FDrawFieldCellEvent(self, DrawColumn.Field, cl, fn, ARow);

Brush.Color := cl;

Font := fn;

end;

end;

Highlight := HighlightCell(ACol, ARow, Value, AState);

if Highlight and (not FWZebra) then

begin

Brush.Color := clHighlight;

Font.Color := clHighlightText;

end;

if DefaultDrawing then

DefaultDrawColumnCell(ARect, ACol, DrawColumn, AState);

if Columns.State = csDefault then

DrawDataCell(ARect, DrawColumn.Field, AState);

DrawColumnCell(ARect, ACol, DrawColumn, AState);

finally

DataLink.Activerecord := OldActive;

end;

if DefaultDrawing and (gdSelected in AState) and

((dgAlwaysShowSelection in Options) or Focused)

and not (csDesigning in Componentstate)

and not (dgRowSelect in Options)

and (ValidParentForm(self).ActiveControl = self) then

begin

//显示当前光标处为蓝底黄字,同时加粗显示

Windows.DrawFocusRect(Handle, ARect);

Canvas.Brush.COlor := clBlue;

Canvas.FillRect(ARect);

Canvas.Font.Color := clYellow;

Canvas.Font.Style := [fsBold];

DefaultDrawColumnCell(ARect, ACol, DrawColumn, AState);

end;

end;

end;

if (gdFixed in AState) and ([dgRowLines, dgColLines] * Options =

[dgRowLines, dgColLines]) then

begin

InflateRect(ARect, -2, -2);

DrawEdge(Canvas.Handle, ARect, BDR_RAISEDINNER, BF_BOTTOMRIGHT);

DrawEdge(Canvas.Handle, ARect, BDR_SUNKENINNER, BF_TOPLEFT);

end;

end;

//如果移动光标等,则需要刷新显示DBGrid

procedure TNewDBGrid.Scroll(Distance: Integer);

begin

inherited Scroll(Distance);

delphi中TDBGrid的使用 c 句柄 tdbgrid
refresh;

end;

end.

-----------------------------------------------

在DBGrid控件中显示图形  如果在数据库中设置了一个为BLOB类型的字段用于保存图形,在使用DBGrid控件显示时,在表格中显示的是BLOB,而无法显示出图形,当然,有一些第三方控件可以显示出图形,但是要去找第三方控件不是一件容易的事,而且有些好用的都需要付费。能不能在DBGrid中显示图形呢?答案是肯定的。

在DBGrid的OnDrawCell事件中加入如下代码即可在DBGrid控件中显示图形。

var

Bmp: TBitmap;

begin

if (Column.Field.DataTyp = ftBLOB) or (Column.Field.DataTyp = ftGraphic) then

begin

Bmp:=TBitmap.Create;

try

Bmp.Assign(Column.Field);

DBGrid1.Canvas.StretchDraw(Rect,Bmp);

Bmp.Free;

Except

Bmp.Free;

end;

end;

end;

-----------------------------------------------

将 DBGrid 中的内容输出至 Excel 或 ClipBoard

//注意:下面的方法必须包含 ComObj, Excel97 单元

//-----------------------------------------------------------

// if toExcel = false, export dbgrid contents to the Clipboard

// if toExcel = true, export dbgrid to Microsoft Excel

procedure ExportDBGrid(toExcel: Boolean);

var

bm: TBookmark;

col, row: Integer;

sline: String;

mem: TMemo;

ExcelApp: Variant;

begin

Screen.Cursor := crHourglass;

DBGrid1.DataSource.DataSet.DisableControls;

bm := DBGrid1.DataSource.DataSet.GetBookmark;

DBGrid1.DataSource.DataSet.First;

// create the Excel object

if toExcel then

begin

ExcelApp := CreateOleObject('Excel.Application');

ExcelApp.WorkBooks.Add(xlWBatWorkSheet);

ExcelApp.WorkBooks[1].WorkSheets[1].Name := 'Grid Data';

end;

// First we send the data to a memo

// works faster than doing it directly to Excel

mem := TMemo.Create(Self);

mem.Visible := false;

mem.Parent := MainForm;

mem.Clear;

sline := '';

// add the info for the column names

for col := 0 to DBGrid1.FieldCount-1 do

sline := sline + DBGrid1.Fields[col].DisplayLabel + #9;

mem.Lines.Add(sline);

// get the data into the memo

for row := 0 to DBGrid1.DataSource.DataSet.RecordCount-1 do

begin

sline := '';

for col := 0 to DBGrid1.FieldCount-1 do

sline := sline + DBGrid1.Fields[col].AsString + #9;

mem.Lines.Add(sline);

DBGrid1.DataSource.DataSet.Next;

end;

// we copy the data to the clipboard

mem.SelectAll;

mem.CopyToClipboard;

// if needed, send it to Excel

// if not, we already have it in the clipboard

if toExcel then

begin

ExcelApp.Workbooks[1].WorkSheets['Grid Data'].Paste;

ExcelApp.Visible := true;

end;

FreeAndNil(mem);

// FreeAndNil(ExcelApp);

DBGrid1.DataSource.DataSet.GotoBookmark(bm);

DBGrid1.DataSource.DataSet.FreeBookmark(bm);

DBGrid1.DataSource.DataSet.EnableControls;

Screen.Cursor := crDefault;

end;

-----------------------------------------------

数据网格自动适应宽度///////源代码开始

uses

Math;

function DBGridRecordSize(mColumn: TColumn): Boolean;

{ 返回记录数据网格列显示最大宽度是否成功 }

begin

Result := False;

if not Assigned(mColumn.Field) then Exit;

mColumn.Field.Tag := Max(mColumn.Field.Tag,

TDBGrid(mColumn.Grid).Canvas.TextWidth(mColumn.Field.DisplayText));

Result := True;

end; { DBGridRecordSize }

function DBGridAutoSize(mDBGrid: TDBGrid; mOffset: Integer = 5): Boolean;

{ 返回数据网格自动适应宽度是否成功 }

var

I: Integer;

begin

Result := False;

if not Assigned(mDBGrid) then Exit;

if not Assigned(mDBGrid.DataSource) then Exit;

if not Assigned(mDBGrid.DataSource.DataSet) then Exit;

if not mDBGrid.DataSource.DataSet.Active then Exit;

for I := 0 to mDBGrid.Columns.Count - 1 do begin

if not mDBGrid.Columns[I].Visible then Continue;

if Assigned(mDBGrid.Columns[I].Field) then

mDBGrid.Columns[I].Width := Max(mDBGrid.Columns[I].Field.Tag,

mDBGrid.Canvas.TextWidth(mDBGrid.Columns[I].Title.Caption)) + mOffset

else mDBGrid.Columns[I].Width :=

mDBGrid.Canvas.TextWidth(mDBGrid.Columns[I].Title.Caption) + mOffset;

mDBGrid.Refresh;

end;

Result := True;

end; { DBGridAutoSize }

///////源代码结束

///////使用示例开始

procedure TForm1.DBGrid1DrawColumnCell(Sender: TObject; const Rect: TRect;

DataCol: Integer; Column: TColumn; State: TGridDrawState);

begin

DBGridRecordSize(Column);

end;

procedure TForm1.Button1Click(Sender: TObject);

begin

DBGridAutoSize(DBGrid1);

end;

///////使用示例结束

  

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