WebCast听课录(7)

课程名：Windows应用程序开发入门到精通四：Windows窗体开发中的面向对象概念

1,自定义控件的开发。<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

最简单的控件自定义是重写公共控件的方法。例如，可以重写 TextBox 控件的 OnKeyPress 继承方法，提供将输入限制为数字字符的代码。

publicclassNumricTextBox:System.Windows.Forms.TextBox
{
boolallowSpace=false;//不允许出现空格

protectedoverridevoidOnKeyPress(KeyPressEventArgse)
{//限制输入字符为数字，小数点，负号，Backspace键
base.OnKeyPress(e);

NumberFormatInfonumberFormatInfo=System.Globalization.CultureInfo.CurrentCulture.NumberFormat;
stringdecimalSeparator=numberFormatInfo.NumberDecimalSeparator;
stringgroupSeparator=numberFormatInfo.NumberGroupSeparator;
stringnegativeSign=numberFormatInfo.NegativeSign;

stringkeyInput=e.KeyChar.ToString();

if(Char.IsDigit(e.KeyChar))
{
//输入为数字
}
elseif(keyInput.Equals(decimalSeparator)||keyInput.Equals(groupSeparator)||
keyInput.Equals(negativeSign))
{
//输入小数分隔符号
}
elseif(e.KeyChar=='/b')
{
//Backspace键
}
elseif(this.allowSpace&&e.KeyChar=='')
{

}
else
{
e.Handled=true;//通知父类事件已经处理过了，父类不必再响应
}
}

publicintIntValue
{
get
{
returnInt32.Parse(this.Text);
}
}

publicdecimalDecimalValue
{
get
{
returnDecimal.Parse(this.Text);
}
}

publicboolAllowSpace
{
set
{
this.allowSpace=value;
}

get
{
returnthis.allowSpace;
}
}

}

2, “组合”和“聚合”的区别到底是什么呢？用接口来代替继承更易于应对变化？

3，Observer模式实例

publicinterfaceISubject
{
}

publicinterfaceIObserver
{
ISubjectSubject
{
set;
}
}

publicclassMainSubject:ISubject
{
publiceventEventHandlerSelectedChanged;
privateintm_selected;

publicintSelected
{
get
{
returnm_selected;
}
set
{
m_selected=value;
if(SelectedChanged!=null)
{
SelectedChanged(this,EventArgs.Empty);
}
}
}

publicMainSubject()
{
}
}

publicclassButtons:System.Windows.Forms.UserControl,IObserver
{
privateSystem.Windows.Forms.Buttonbutton1;
privateSystem.Windows.Forms.Buttonbutton2;
privateSystem.Windows.Forms.Buttonbutton3;

privateMainSubjectm_subject;

privatevoidbutton1_Click(objectsender,System.EventArgse)
{
this.m_subject.Selected=1;
}

privatevoidbutton2_Click(objectsender,System.EventArgse)
{
this.m_subject.Selected=2;
}

privatevoidbutton3_Click(objectsender,System.EventArgse)
{
this.m_subject.Selected=3;
}
IObserverMembers#regionIObserverMembers

publicISubjectSubject
{
set
{
m_subject=(MainSubject)value;
}
}

#endregion
}

publicclassViews:System.Windows.Forms.UserControl,IObserver
{
privateSystem.Windows.Forms.TextBoxtextBox1;
privateMainSubjectm_subject;

IObserverMembers#regionIObserverMembers

publicISubjectSubject
{
set
{
m_subject=(MainSubject)value;
m_subject.SelectedChanged+=newEventHandler(m_subject_SelectedChanged);
}
}

#endregion

privatevoidm_subject_SelectedChanged(objectsender,EventArgse)
{
this.textBox1.Text=m_subject.Selected.ToString();
}
}

publicclassForm1:System.Windows.Forms.Form
{
privateObserverPattern.Buttonsbuttons1;
privateObserverPattern.Viewsviews1;
privateMainSubjectm_subject;

privateSystem.ComponentModel.Containercomponents=null;

publicForm1()
{
InitializeComponent();
m_subject=newMainSubject();
this.buttons1.Subject=m_subject;
this.views1.Subject=m_subject;
}
}