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<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> {</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> Receiver = receiver;</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> Method = method;</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> }</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> public void Execute(object sender, EventArgs e)</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> {</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> Method.Invoke(Receiver, new object[] {} );</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> }</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> public readonly object Receiver;</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> public readonly MethodInfo Method;</span></p>
<p class="2" style="MARGIN-TOP: 0cm; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US">}</span></p>
<p class="MsoNormal" style="LINE-HEIGHT: 16pt"><span style="FONT-FAMILY: 宋体">该类只提供了一个</span><span lang="EN-US">EventHandler</span><span style="FONT-FAMILY: 宋体">委托</span><span lang="EN-US">(Execute</span><span style="FONT-FAMILY: 宋体">方法</span><span lang="EN-US">)</span><span style="FONT-FAMILY: 宋体">，它在接收器对象上调用所希望的方法。本例显示了两种不同类型的行<span style="LETTER-SPACING: -1pt">——</span></span><span style="LETTER-SPACING: -1pt"> </span><span lang="EN-US">Customers</span><span style="FONT-FAMILY: 宋体">表中的行和</span><span lang="EN-US">Orders</span><span style="FONT-FAMILY: 宋体">表中的行。自然，这些类型的数据的处理选项都是不同的。图</span><span lang="EN-US">22-29</span><span style="FONT-FAMILY: 宋体">显示了可以应用到</span><span lang="EN-US">Customer</span><span style="FONT-FAMILY: 宋体">行上的操作。图</span><span lang="EN-US">22-30</span><span style="FONT-FAMILY: 宋体">显示了可以应用到</span><span lang="EN-US">Order</span><span style="FONT-FAMILY: 宋体">行上的操作。</span></p>
<p align="center"><span lang="EN-US"><img height="192" src="22/image030.jpg" width="322" alt="" /></span></p>
<p style="FTEL: 8.15pt" align="center"><span style="FONT-FAMILY: 宋体">图</span><span lang="EN-US"> 22-30</span></p>
<h4 style="FTEL: 21.45pt"><span lang="EN-US">4. </span><span style="FONT-FAMILY: 黑体">获得选中的行</span></h4>
<p class="MsoNormal" style="LINE-HEIGHT: 16pt"><span style="FONT-FAMILY: 宋体">这个示例的最后一个问题是如何处理</span><span lang="EN-US">DataSet</span><span style="FONT-FAMILY: 宋体">中用户选择的行。首先考虑“它必须是</span><span lang="EN-US">DataGrid</span><span style="FONT-FAMILY: 宋体">的一个属性”，但在</span><span lang="EN-US">DataGrid</span><span style="FONT-FAMILY: 宋体">上不能使用这个属性。查看一下从</span><span lang="EN-US">MouseUp()</span><span style="FONT-FAMILY: 宋体">事件处理程序中获得的测试信息，</span> <span style="FONT-FAMILY: 宋体">但只有在显示一个</span><span lang="EN-US">DataTable</span><span style="FONT-FAMILY: 宋体">中的数据时，这才有一定的帮助。</span></p>
<p class="MsoToc1" style="LINE-HEIGHT: 16pt"><span style="FONT-FAMILY: 宋体">下面介绍如何填充网格：</span></p>
<p class="2" style="MARGIN-TOP: 8.15pt; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US">dataGrid.SetDataBinding(ds,"Customers");</span></p>
<p class="MsoNormal" style="LINE-HEIGHT: 16pt"><span style="FONT-FAMILY: 宋体">这个方法给</span><span lang="EN-US">BindingContext</span><span style="FONT-FAMILY: 宋体">添加一个新的</span><span lang="EN-US">CurrencyManager</span><span style="FONT-FAMILY: 宋体">，它表示当前数据表和</span><span lang="EN-US">DataSet</span><span style="FONT-FAMILY: 宋体">。现在，</span><span lang="EN-US">DataGrid</span><span style="FONT-FAMILY: 宋体">有两个属性</span><span lang="EN-US">DataSource</span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US">DataMember</span><span style="FONT-FAMILY: 宋体">，在调用</span><span lang="EN-US">SetDataBinding()</span><span style="FONT-FAMILY: 宋体">时设置它们。本例中的</span><span lang="EN-US">DataSource</span><span style="FONT-FAMILY: 宋体">是一个</span><span lang="EN-US">DataSet</span><span style="FONT-FAMILY: 宋体">，</span><span lang="EN-US">DataMember</span><span style="FONT-FAMILY: 宋体">是</span><span lang="EN-US">Customers</span><span style="FONT-FAMILY: 宋体">。</span></p>
<p class="MsoNormal" style="LINE-HEIGHT: 16pt"><span style="FONT-FAMILY: 宋体">给定数据源和一个数据成员，以及窗体的</span><span lang="EN-US">BindingContext</span><span style="FONT-FAMILY: 宋体">，就可以使用下面的代码查找当前行：</span></p>
<p class="2" style="MARGIN-TOP: 8.15pt; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US"> protected void dataGrid_MouseUp(object sender, MouseEventArgs e)</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> {</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> // Perform a hit test</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> if(e.Button == MouseButtons.Right)</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> {</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> // Find which row the user clicked on, if any</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> DataGrid.HitTestInfo hti = dataGrid.HitTest(e.X, e.Y);</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> </span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> // Check if the user hit a cell</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> if(hti.Type == DataGrid.HitTestType.Cell)</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> {</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> // Find the DataRow that corresponds to the cell </span></p>
<p class="2" style="MARGIN-TOP: 0cm; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US"> //the user has clicked upon</span></p>
<p class="MsoNormal" style="LINE-HEIGHT: 16pt"><span style="FONT-FAMILY: 宋体">在调用</span><span lang="EN-US">dataGrid.HitTest()</span><span style="FONT-FAMILY: 宋体">确定用户在什么地方单击了鼠标后，就要为</span><span lang="EN-US">DataGrid</span><span style="FONT-FAMILY: 宋体">检索</span><span lang="EN-US">BindingManagerBase</span><span style="FONT-FAMILY: 宋体">实例了：</span></p>
<p class="2" style="MARGIN-TOP: 8.15pt; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US"> BindingManagerBase bmb = this.BindingContext[ dataGrid.DataSource, </span></p>
<p class="2" style="MARGIN-TOP: 0cm; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US"> dataGrid.DataMember];</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">它使用了</span><span lang="EN-US">DataGrid</span><span style="FONT-FAMILY: 宋体">的</span><span lang="EN-US">DataSource </span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US">DataMember</span><span style="FONT-FAMILY: 宋体">，给要返回的对象命名。现在只需查找用户单击的行，显示关联菜单。右击了一个行后，当前行的指示符一般不会移动，但这还不够，还要移动行的指示符，再显示弹出菜单。</span><span lang="EN-US">HitTestInfo</span><span style="FONT-FAMILY: 宋体">对象中有行号，所以只需移动</span><span lang="EN-US">BindindManagerBase</span><span style="FONT-FAMILY: 宋体">对象的当前位置：</span></p>
<p class="2" style="MARGIN-TOP: 8.15pt; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US"> bmb.Position = hti.Row;</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">这会改变单元格的指示符，同时意味着在调用类来获取</span><span lang="EN-US">Row</span><span style="FONT-FAMILY: 宋体">时，将返回当前行，而不是上次选择的行：</span></p>
<p class="2" style="MARGIN-TOP: 8.15pt; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US"> DataRowView drv = bmb.Current as DataRowView;</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> if(drv != null)</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> {</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> ContextDataRow ctx = drv.Row as ContextDataRow;</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> if(ctx != null) ctx.PopupMenu(dataGrid,e.X,e.Y);</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> }</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> }</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; LINE-HEIGHT: 13pt; FTEL: 18.45pt"><span lang="EN-US"> }</span></p>
<p class="2" style="MARGIN-TOP: 0cm; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US"> }</span></p>
<p class="MsoNormal" style="LINE-HEIGHT: 16pt"><span style="FONT-FAMILY: 宋体">在</span><span lang="EN-US">DataGrid</span><span style="FONT-FAMILY: 宋体">显示</span><span lang="EN-US">DataSet</span><span style="FONT-FAMILY: 宋体">中的元素时，</span><span lang="EN-US">BindingManagerBase</span><span style="FONT-FAMILY: 宋体">集合中的</span><span lang="EN-US">Current</span><span style="FONT-FAMILY: 宋体">对象是一个</span><span lang="EN-US">DataRowView</span><span style="FONT-FAMILY: 宋体">，它在上面的代码中用一个明确的类型转换进行了测试，如果成功，就可以获取</span><span lang="EN-US">DataRowView</span><span style="FONT-FAMILY: 宋体">包装的实际行，执行另一个类型转换，确定它是否是</span><span lang="EN-US">ContextDataRow</span><span style="FONT-FAMILY: 宋体">，最终会弹出一个菜单。</span></p>
<p class="MsoNormal" style="LINE-HEIGHT: 16pt"><span style="FONT-FAMILY: 宋体">在本例中，创建了两个数据表<span style="LETTER-SPACING: -1pt">——</span></span><span style="LETTER-SPACING: -1pt"> </span><span lang="EN-US">customers</span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US">orders</span><span style="FONT-FAMILY: 宋体">，定义了这些表之间的关系，这样在用户单击</span><span lang="EN-US">CustomerOrders</span><span style="FONT-FAMILY: 宋体">时，会得到一个订单的过滤列表。此时，</span><span lang="EN-US">DataGrid</span><span style="FONT-FAMILY: 宋体">把</span><span lang="EN-US">DataMember</span><span style="FONT-FAMILY: 宋体">从</span><span lang="EN-US">Customers</span><span style="FONT-FAMILY: 宋体">变为</span><span lang="EN-US">Customers.CustomerOrders</span><span style="FONT-FAMILY: 宋体">，</span><span lang="EN-US">BindingContext</span><span style="FONT-FAMILY: 宋体">索引器使用它获取要显示的数据。</span></p></div>
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<h1 id="divCurrentNode2" style="color: #b83507; width: 100%; text-align: left; font-size: 12px; padding-left: 2px">当前章节:<a href='100165633.htm'><font color='red'>22.3.6 其他常见的要求</font></a></h1>
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<div style='float:left;width:49%'>·<a href='100165630.htm'>22.3.3 生成DataSet</a></div><div style='float:right;width:49%'>·<a href='100165631.htm'>22.3.4 更新数据源</a></div><div style='float:left;width:49%'>·<a href='100165632.htm'>22.3.5 构建模式</a></div><div style='float:right;width:49%'>·<a href='100165634.htm'>22.4 小结</a></div><div style='float:left;width:49%'>·<a href='100165635.htm'>23.1 .NET支持的XML标准</a></div><div style='float:right;width:49%'>·<a href='100165636.htm'>23.2 System.Xml命名空间</a></div></div>
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