所以我的第一次尝试完成了后面的代码,现在我正在尝试重构我的代码以使用MVVM模式,遵循MVVM 在框信息中的指导.
我已经创建了一个viewmodel类来匹配我的视图类,并且我将代码从代码中移出到viewmodel中,从命令开始.
我的第一个障碍是尝试实现一个"关闭"按钮,如果数据未被修改则关闭窗口.我已经装配了一个CloseCommand来替换'onClick'方法,除了代码试图运行的地方外,一切都很好this.Close().显然,由于代码已从窗口移动到普通类,因此'this'不是窗口,因此不可关闭.但是,根据MVVM,viewmodel不知道视图,所以我无法调用view.Close().
有人可以建议我如何从viewmodel命令关闭窗口？
如何使用IValueConverter将空值转换为布尔值？
我正在使用wpf来尝试显示一堆布尔值(在复选框中).创建新记录时,这些值为空,并在复选框中显示为"不确定".我希望空值出现并保存为"false"值.
我尝试创建一个NullToBoolean转换器,它从数据库中获取空值并将它们显示为false,然后在用户点击保存时将它们保存为false.(基本上,我试图避免用户必须在复选框中单击两次(一次使其成为真,然后再次使其成为假).这似乎适用于导入 - 即空值显示为false - 但除非我进行双击跳舞,当我保存时,数据库中的值不会改变.
我的转换器:
[ValueConversion(typeof(bool), typeof(bool))]
public class NullBooleanConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
if (value != null)
{
return value;
}
return false;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
if (value != null)
{
return value;
}
return null;
}
}
我试图让Converter工作的复选框之一:
<CheckBox Grid.Column="1" Grid.Row="0" Padding="5" Margin="5" VerticalAlignment="Center" Name="chkVarianceDescriptionProvided" IsThreeState="False">
<CheckBox.IsChecked>
<Binding Path="VarianceDescriptionProvided" Mode="TwoWay">
<Binding.Converter>
<utils:NullBooleanConverter />
</Binding.Converter> …我有一个实体框架项目在我的机器上工作正常,但从网络运行时会出现问题.最近对该项目的更改包括添加Dynamic Linq dll(System.Linq.Dynamic)
当我从网络调试它时,VS报告: The type initializer for 'System.Data.Entity.Internal.AppConfig' threw an exception
内部异常是:"无法加载文件或程序集'EntityFramework,Version = 4.4.0.0,Culture = neutral,PublicKeyToken = b77a5c561934e089'或其依赖项之一.找到的程序集的清单定义与程序集引用不匹配.(例外情况HRESULT:0x80131040)":"EntityFramework,Version = 4.4.0.0,Culture = neutral,PublicKeyToken = b77a5c561934e089"}
我尝试了通常的技巧:packages从项目的根目录中删除目录,从包管理器控制台卸载并重新安装,但无济于事.
我的app.config:
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<configSections>
<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
<sectionGroup name="applicationSettings" type="System.Configuration.ApplicationSettingsGroup, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
<section name="LGFinance.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
</sectionGroup>
<!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
</configSections>
<connectionStrings>
<add name="LGFinanceEntities" connectionString="metadata=res://*/Model.LGFinanceContext.csdl|res://*/Model.LGFinanceContext.ssdl|res://*/Model.LGFinanceContext.msl;provider=System.Data.SqlClient; provider connection string='data source=lightning;initial …解决方案：需要转换的.csv文件的文件路径错误。
我在尝试运行批处理spring应用程序时遇到一些问题。
目标：我想读取一个csv文件并将其加载到类上（我的老板告诉我），我确定知道的是我使用的代码示例直接将数据加载到MySQL。
在这里，我发布了我的项目的图片：
http://i.stack.imgur.com/ieEmK.png
-这里是文件-
App.java
package springbach;
import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobExecution;
import org.springframework.batch.core.JobParameters;
import org.springframework.batch.core.launch.JobLauncher;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class App {
public static void main(String[] args) {
String[] springConfig =
{ "database.xml",
"context.xml",
"job-report.xml"
};
ApplicationContext context =
new ClassPathXmlApplicationContext(springConfig);
JobLauncher jobLauncher = (JobLauncher) context.getBean("jobLauncher");
Job job = (Job) context.getBean("reportJob");
try {
JobExecution execution = jobLauncher.run(job, new JobParameters());
System.out.println("Exit Status : " + execution.getStatus());
} catch (Exception e) {
e.printStackTrace();
}
System.out.println("Done");
}
}
Report.java …
如何将计算布尔 ( bit) 列添加到依赖于其他两个布尔列的 SQL Server 表中？（我更喜欢 SSMS 解决方案）。
我可以使用以下命令获得具有正确值的计算列：
case when ([ColumnA]=(1)) AND ([ColumnB]=(0)) then (1) else (0) end
但当我在 C# 中使用数据时，结果列的类型int会失败
环顾四周，似乎我需要使用一个CAST语句，但我还没有弄清楚语法。我知道这行不通：
cast (case when ([ColumnA]=(1)) AND ([ColumnB]=(0)) then (1) else (0) end) as bit
我应该怎么办？
我在测试类中将随机数放入数组时遇到了麻烦.代码在java中.我无法单独完成,因为最终我必须使用多达600个值来填充数组.这是测试类:
import java.util.Random;
public class test {
/**
* @param args
*/
public static void main(String[] args) {
int size = 1000;
int max = 5000;
int[] array = new int[size];
int loop = 0;
Random generator = new Random();
//Write a loop that generates 1000 integers and
//store them in the array using generator.nextInt(max)
generator.nextInt(max); //generating one
//I need to generate 1000
//So I need some kind of loop that will generate 1000 numbers.
for (int i =0; i<1000; …类似于WPF：如何仅绑定到集合中的一项，不使用 ItemsControl，因为我不想显示所有项，除非集合与主绑定项相关。所有数据都通过 EntityFramework 传入。与链接的问题一样，xaml 解释得最好：
<StackPanel Grid.Row="1" Orientation="Horizontal" DataContext="{Binding CurrentCustomer}">
<StackPanel Orientation="Horizontal">
<TextBlock Text="Total Orders:" />
<TextBlock Text="{Binding Orders.Count}" />
</StackPanel >
<StackPanel Orientation="Horizontal">
<TextBlock Text="First Order:" />
<TextBlock Text="{Binding Orders.First.OrderDate}" />
</StackPanel >
</StackPanel>
正如您所看到的，我猜测由于我可以使用“Orders.Count”获取相关订单的计数，因此我尝试使用相同的 linq 语法来尝试检索 Orders.First （我也尝试过 Orders.FirstOrDefault），但是这是行不通的。
查看链接的问题，我尝试了Sheridan的 '[]' 语法，但 Orders[0].OrderDate 给出了输出错误： System.Windows.Data Error: 40 : BindingExpression path error: '[]' property not found on 'object' ''HashSet'1' (HashCode=37425772)'. BindingExpression:Path=Orders[0].OrderDate; DataItem='Customer_<BigLongIdentityString>' (HashCode=21972018); target element is 'TextBlock' (Name=''); target property is 'Text' (type 'String')。 …
我正在为我的论文使用c ++和NS3.所以我想用stl函数排序对struct的向量进行排序,所以我将把我的头文件发布到我的向量所在的位置,我将解释我想做什么.
#include "ns3/net-device.h"
#include "ns3/object.h"
#include "ns3/log.h"
#include <vector>
#include <stdint.h>
#include "miscellaneous.h"
namespace ns3 {
/**
* \brief The UeRecord class is developed in order to store at the eNodeB
* all information (such as feedback cqi, mac address etc...) of a UE registered
* into that eNodeB. All UE records are managed by the UeManager class
*/
class UeRecord : public Object
{
public:
UeRecord ();
~UeRecord ();
/**
* \brief CqiFeedbacks represents a list of CQI …使用EntityFramework,我在App_Code\DAL中创建了一个EntityDataModel(.edmx文件).在向导中,我将实体命名为"DLGDBEntities".我EntityDataSource在.aspx中有一些s,我将OnContextCreating属性设置为'UseSurveyContext',如下所示:
protected void UseSurveyContext(object sender, EntityDataSourceContextCreatingEventArgs e)
{
e.Context = surveyContext;
}
surveyContext的设置代码如下:
DLGDBEntities surveyContext;
并在Page_Load中:
surveyContext = new DLGDBEntities();
以上所有内容看起来与我在每个教程中看到的代码相同(例如:http://msdn.microsoft.com/en-us/library/cc668193.aspx#1),我可以发誓我已经拥有了它工作.
然而,现在,我收到错误: Cannot implicitly convert type 'DAL.DLGDBEntities' to 'System.Data.Objects.ObjectContext'
我做错了什么,为什么之前有效呢？
我正在尝试使用递归编写一个迷宫求解器,它似乎尝试每个方向一次,然后停止,我无法弄清楚为什么.如果您发现问题,请告诉我.键0是开放空间1是墙2是路径3的一部分是迷宫的末端
public class Maze{
public static void main(String[] args){
int[][] maze =
{{1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
{0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1},
{1,0,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,0,1,0,1},
{1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,1},
{1,0,1,0,1,1,1,0,1,0,1,1,1,1,1,1,1,1,1,0,1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1},
{1,0,1,0,1,0,1,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1},
{1,0,1,1,1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,0,1},
{1,0,0,0,0,0,1,0,0,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,1},
{1,1,1,0,1,1,1,1,1,1,1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1},
{1,0,1,0,1,0,0,0,0,0,0,0,1,0,1,0,1,0,1,0,1,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,1},
{1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,0,1,1,1,0,1,0,1,1,1},
{1,0,1,0,1,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,1},
{1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1},
{1,0,1,0,1,0,1,0,1,0,0,0,1,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1},
{1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,0,1,1,1,1,1,1,1,1,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,0,1,0,1,1,1,1,1,0,1},
{1,0,0,0,1,0,1,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,0,0,1},
{1,0,1,1,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,0,1},
{1,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,1,0,1},
{1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1},
{1,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,1},
{1,0,1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,1,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,0,1,0,1},
{1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,1,0,1},
{1,1,1,0,1,0,1,1,1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1},
{1,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,1},
{1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,0,1,0,1},
{1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,1},
{1,0,1,1,1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,1,1,0,1,0,1,0,1},
{1,0,0,0,0,0,0,0,1,0,1,0,1,0,1,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,1,0,1,0,0,0,1,0,1,0,1},
{1,0,1,1,1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,1,1,1,1,0,1},
{1,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,1,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,1},
{1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,0,1,0,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,0,1,0,1},
{1,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,1},
{1,0,1,1,1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,0,1,0,1,0,1,0,1},
{1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,1},
{1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1}};
boolean[][] posCheck = new boolean[maze.length][maze[0].length];
int r = 0;
int c = 0;
for(int row = 0; row < maze.length; row++){
for(int col = 0; col < maze[row].length; col++){
if(maze[row][col]==0){
r = row; …我UserControl在另一个中有一个“子项” UserControl（它充当 a 中的 TabItem TabControl）。在子项UserControl和 TabItem 祖先之间是许多其他控件（例如：Grids、 a StackPanel，可能是 aScrollViewer等）。
UserControl我想访问我的孩子中TabItem 的属性UserControl，并自定义一个通常 建议的递归函数，该函数沿着可视化树向上移动。但是，这总是在第一次空检查时返回true，直到我在逻辑树上添加查询。
代码：
public MyTabItem FindParentTabItem(DependencyObject child)
{
DependencyObject parent = VisualTreeHelper.GetParent(child) ?? LogicalTreeHelper.GetParent(child);
// are we at the top of the tree
if (parent == null)
{
return null;
}
MyTabItem parentTabItem = parent as MyTabItem;
if (parentTabItem != null)
{
return parentTabItem;
}
else
{
//use recursion until …