全部展开
全部折叠该简单的设计器具有可以切换启用或者禁用状态的按钮，取决于剪贴板以及Undo缓冲区是否为空，是否有文件被加载，等等。所有这些功能在一个单一的方法中实现，称为UpdateUI。
UpdateUI被频繁调用以确保UI真实地反映应用程序的状态。第一次调用应该在响应Form_Load事件的方法中，用来初始化工具栏以及窗体的标题。在将下面的代码粘贴到工程之后，请记得将工具栏控件内的按钮名称匹配UpdateUI例程中使用到的名称。
将下面的代码添加进来以更新用户界面：
Visual Basic
| Visual Basic |
拷贝代码
|
|---|---|
' 在启动时更新界面，以显示窗体标题以并禁用剪贴板以及
' 撤销/重做按钮
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
UpdateUI()
End Sub
Private Sub UpdateUI()
' 更新标题
_fileName = _appName
If _fileName.Length > 0 Then
_fileName = String.Format("{0} - [{1}]", _appName, _fileName)
If _dirty Then _fileName = _fileName + " *"
End If
' 按下/释放表示设计或者预览模式的按钮
Dim design As Boolean = _c1rd.Visible AndAlso (Not IsNothing(_c1rd.Report))
_btnDesign.Pushed = design
_btnPreview.Pushed = Not design
' 启用/禁用按钮
_btnCut.Enabled = design AndAlso _c1rd.ClipboardHandler.CanCut
_btnCopy.Enabled = design AndAlso _c1rd.ClipboardHandler.CanCut
_btnPaste.Enabled = design AndAlso _c1rd.ClipboardHandler.CanPaste
_btnUndo.Enabled = design AndAlso _c1rd.UndoStack.CanUndo
_btnRedo.Enabled = design AndAlso _c1rd.UndoStack.CanRedo
Dim reportSelected As Boolean = design AndAlso Not (IsNothing(_list.SelectedItem))
_btnAddReport.Enabled = _c1rd.Visible
_btnDelReport.Enabled = reportSelected
_btnAddField.Enabled = reportSelected
_btnAddLabel.Enabled = reportSelected
End Sub
|
|
C#
| C# |
拷贝代码
|
|---|---|
// 在启动时更新界面，以显示窗体标题以并禁用剪贴板以及
// 撤销/重做按钮
private void Form1_Load(object sender, System.EventArgs e)
{
UpdateUI();
}
private void UpdateUI()
{
// update caption
Text = (_fileName != null && _fileName.Length > 0)
? string.Format("{0} - [{1}] {2}", _appName, _fileName, _dirty? "*": "")
: _appName;
// push/release design/preview mode buttons
bool design = _c1rd.Visible && _c1rd.Report != null;
_btnDesign.Pushed = design;
_btnPreview.Pushed = !design;
// 启用/禁用按钮
_btnCut.Enabled = design && _c1rd.ClipboardHandler.CanCut;
_btnCopy.Enabled = design && _c1rd.ClipboardHandler.CanCut;
_btnPaste.Enabled = design && _c1rd.ClipboardHandler.CanPaste;
_btnUndo.Enabled = design && _c1rd.UndoStack.CanUndo;
_btnRedo.Enabled = design && _c1rd.UndoStack.CanRedo;
bool reportSelected = design && _list.SelectedItem != null;
_btnAddReport.Enabled = _c1rd.Visible;
_btnDelReport.Enabled = reportSelected;
_btnAddField.Enabled = reportSelected;
_btnAddLabel.Enabled = reportSelected;
}
|
|
请注意在这里UpdateUI方法是如何通过使用 CaCanCut, CanPaste, CanUndo, 以及CanRedo属性启用或禁用工具栏按钮的。