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数据集处理成可视树,数据网格自动适应宽度

2006-09-20 22:14 344 查看

作者 : jackgao

标题 : 标题:数据集处理成可视树,数据网格自动适应宽度

关键字: 处理父节点标识字段、节点文本字段、节点标识字段这种表结构,数据网格自动适应宽度

分类 : 开发技巧

密级 : 参赛

(评分:★★ , 回复: 6, 阅读: 804)
说明:处理父节点标识字段、节点文本字段、节点标识字段这种表结构
支持:gzpwr@163.com

///////Begin Source
function DataSetToTreeNode(mDataSet: TDataSet;
mFieldNameParent: string; //父节点标识字段名
mFieldNameTreeText: string; //节点文本字段名
mFieldNameTreeId: string; //节点标识字段名
mTreeView: TTreeView; mTreeNode: TTreeNode;
mParentText: string): Boolean;
var
vTreeNode: TTreeNode;
vFieldValues: Variant;
vFieldNames: string;
begin
Result := False;
if not Assigned(mDataSet) then Exit;
if not Assigned(mTreeView) then Exit;
if not mDataSet.Active then Exit;
vFieldNames := Format('%s;%s;%s',
[mFieldNameParent, mFieldNameTreeText, mFieldNameTreeId]);
mDataSet.Filtered := False;
mDataSet.Filter := Format('%s=%s', [mFieldNameParent, QuotedStr(mParentText)]);
mDataSet.Filtered := True;
if mDataSet.RecordCount = 0 then Exit;
mDataSet.First;
while not mDataSet.Eof do begin
vTreeNode := mTreeView.Items.AddChild(mTreeNode,
mDataSet.FieldByName(mFieldNameTreeText).AsString);
vFieldValues := mDataSet[vFieldNames];
DataSetToTreeNode(mDataSet, mFieldNameParent, mFieldNameTreeText,
mFieldNameTreeId, mTreeView, vTreeNode,
mDataSet.FieldByName(mFieldNameTreeId).AsString);
///////Begin 恢复位置
mDataSet.Filtered := False;
mDataSet.Filter := Format('%s=%s', [mFieldNameParent, QuotedStr(mParentText)]);
mDataSet.Filtered := True;
mDataSet.Locate(vFieldNames, vFieldValues, []);
///////End 恢复位置
mDataSet.Next;
end;
Result := True;
end;
///////End Source

///////Begin Demo
procedure TForm1.Button1Click(Sender: Tobject);
begin
TreeView1.Items.Clear;
DataSetToTreeNode(Table1, 'ParentTreeId', 'TreeText', 'TreeId',
TreeView1, nil, 'NULL');
end;
///////End Source

数据网格自动适应宽度
说明:使用DBGrid不可不看

///////Begin Source
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 }
///////End Source

///////Begin Demo
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;
///////End Demo

2003-5-14 9:35:00

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