411单分支选择结构(语 ●【判断】按钮的 Click事件代码为 private void button Click(object sender, routedEventArgs e) int costs=int Parse(txt Costs.Text) int revenue=int Parse(txtRevenue. Text) if(costs >=revenue) if( costs> revenue)∥/成本大于收入则输出亏损信息 IblResult Content="盈利情况:亏损"+( costs- revenue)+"元!" else ∥/成本等于收入则输出持平信息 IbIResult Content="盈利情况:持平"; ∥成本小于收入则输出盈利信息 IblResult Content="盈利情况:盈利"+( revenue- costs)+"元!【判断】按钮的Click事件代码为： private void button_Click(object sender, RoutedEventArgs e) { int costs = int.Parse(txtCosts.Text); int revenue = int.Parse(txtRevenue.Text); if (costs >= revenue) { if (costs > revenue) // 成本大于收入则输出亏损信息 lblResult.Content = "盈利情况：亏损" + (costs - revenue) + "元！"; else // 成本等于收入则输出持平信息 lblResult.Content = "盈利情况：持平"; } else // 成本小于收入则输出盈利信息 lblResult.Content = "盈利情况：盈利" + (revenue - costs) + "元！"; } 4.1.1 单分支选择结构（if语句）