小编Ind*_*000的帖子

我的问题非常类似于2D背包问题,或切割股票有一个例外......适合容器的矩形可以调整大小和裁剪.但是不允许轮换.

挑战是尽可能少地种植作物并填满整个容器(无任何间隙).

有没有人遇到过类似的算法.任何链接,伪代码非常赞赏.

保持问题通用,但我想应用它来组织固定大小的页面上的照片.

非常感谢

我正在尝试将命令传递给WPF用户控件中的元素.

<UserControl x:Class="MyApp.MyControl"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <!-- shortened -->
    <Button Command="{Binding Command}">
        <Button.Content>
            <!-- shortened -->
        </Button.Content>
    </Button>
</UserControl>

public partial class MyControl : UserControl
{
   public static readonly DependencyProperty CommandProperty
      = DependencyProperty.Register("Command", 
                                           typeof(ICommand), typeof(MyControl));
   //shortened        
   public ICommand Command
   {
      get { return (ICommand)GetValue(CommandProperty); }
      set { SetValue(CommandProperty, value); }
   }
   //shortened
} 

<uc:MyControl Command="{Binding DoStuffCommand}" />  <!-- shortened -->

单击用户控件中的按钮时,没有任何反应.
当我调试时,该Command属性为null.
将命令绑定到用户控件外部的按钮确实有效.
这里出了什么问题？

我需要在第一行下面插入一个新行.使用下面的代码,我需要添加什么来完成它？

Excel.Application excelApp = new Excel.Application();
string myPath = @"Data.xlsx";
excelApp.Workbooks.Open(myPath);

// Get Worksheet
Excel.Worksheet worksheet = excelApp.Worksheets[1];
int rowIndex = 2; int colIndex = 2;
for (int i = 0; i < 10; i++)
{
   excelApp.Cells[rowIndex, colIndex] = "\r123";
}

excelApp.Visible = false;

谢谢 :)

我想动态画一些东西.以下代码显示了我的OnRender.我正在我的程序中的某个地方设置DrawItem,我需要它.但是,当我打电话给DrawItem =5;我必须打电话时,OnRender会被调用吗？

protected override void OnRender(DrawingContext drawingContext)
{
    switch (DrawItem)
    {
        case 1:
            //Draw Item 
            break;
        case 2:
            //Draw Item 
            break;
        case 3:
            //Draw Item 
            break;
        case 4:
            //Draw Item 
            break;
        case 5:
            //Draw Item 
            break;
    }
    base.OnRender(drawingContext)
}

public int DrawItem { get; set; }

我试图将ListView控件绑定到a DataTable,但WPF绑定系统似乎抱怨我指定的绑定路径.

例如,a GridViewColumn定义如下:

<GridViewColumn Header="ColumnTitle" 
 DisplayMemberBinding="{Binding Path=/, 
                        Converter={StaticResource myConverter}}"/>

据我所知(并且MSN似乎支持我),指定Path=/应该对数据集合的当前项进行绑定.

我收到的错误(在跟踪窗口中)是:

System.Windows.Data错误:39:BindingExpression路径错误:''找不到'当前收集项'''OrdersRow'(HashCode = 680171)'.BindingExpression:路径= /; DataItem ='OrdersRow'(HashCode = 680171); target元素是'TextBlock'(Name =''); target属性是'Text'(类型'String')

这给我的印象/甚至不是一个有效的路径,WPF在斜线后期待一些东西.如果是这样,我将如何绑定到当前项目？为什么我首先得到这个错误？

我试图从我的任务中获取返回数据,如果我使用单个var,它可以正常工作,但是当我使用数组或arraylist时,我在任务对象的可用属性方法中看不到RESULT的接口.

var task = Task<BookingListResponse>
           .Factory.StartNew(() => GetServicesFromApi(sc),
                             TaskCreationOptions.LongRunning);
tasks.Add(task);
try
{
   // Wait for all the tasks to finish.
   Task.WaitAll(tasks.ToArray());
}

正如你从代码中看到的那样,如果我把任务放回一个数组并输入任务[1] .Result,它不会暴露'结果',如果我访问任务然后我可以得到它.

我确信我做的事情很傻,所以任何帮助都会很好.

干杯.

保罗.

这是完整的代码:

List<Task> tasks = new List<Task>();

// loop schemes and only call DISTINCT transit api URL's
foreach (Scheme scheme in schemes)
{
   if (url.ContainsKey(scheme.Url))
      continue;

   url.Add(scheme.Url, 0); // add url.

   var sc = new ServiceCriteria();
   sc.Url = scheme.Url;
   sc.CapacityRequirement = capacityRequirement;
   sc.DropOffLocation = dropOffLocation;
   sc.PickUpLocation = pickUpLocation;
   sc.PickUp = pickup;
   sc.TravelTime = travelTime; …

我有以下使用MEF的示例代码:

public interface IFoo<T> 
{}

public class Foo<T> : IFoo<T> 
{}

[Export(typeof(IFoo<String>))]
public class Foo : Foo<String> 
{}

public class Bar<T>
{
   [Import]
   private readonly IFoo<T> foo;
}

static void Main()
{
   var catalog = new AggregateCatalog();
   catalog.Catalogs.Add(new AssemblyCatalog(Assembly.GetExecutingAssembly()));
   var container = new CompositionContainer(catalog);
   container.ComposeParts();

   var bar = new Bar<String>();
   //bar.foo would be null
}

这似乎不起作用 - foo领域是null.这是因为MEF看不到它的类型IFoo<String>吗？

我是MVVM模式的新手,我必须在以下视图中拦截已检查/未检查的操作

SendMessageView.xaml

<ListBox.ItemTemplate>
   <DataTemplate>
      <StackPanel>
         <CheckBox Checked="Specialita_Checked" 
                Unchecked="Specialita_Unchecked"
                Content="{Binding Path=Item.Name}"
                IsChecked="{Binding RelativeSource={RelativeSource FindAncestor,
                            AncestorType={x:Type ListBoxItem}}, 
                            Path=IsSelected,Mode=TwoWay}"/>
      </StackPanel>
   </DataTemplate>
</ListBox.ItemTemplate>

SendMessageView.xaml.cs

private void Specialita_Checked(object sender, System.Windows.RoutedEventArgs e)
{
   var aSendMessageViewModel = (SendMessageViewModel)this.DataContext;
   if (aSendMessageViewModel != null)
   {
      var aCheckBox = (CheckBox)sender;
      aSendMessageViewModel.AddSpecialita(aCheckBox.Content.ToString());
   }
}

aSendMessageViewModel.cs调用的文件是在a内调用SendMessageView.xaml.cs,这是不正确的.帮助我正确使用MVVM模式.

从一起开始使用Typescript和KnockoutJS,我遇到了一个我无法推理的错误.HTML如下所示:

<div class="panel panel-body">
    <div class="list-group" data-bind="foreach: Items()">
        <a href="#" class="list-group-item"
           data-bind="text:Name, click: $parent.SetCurrent">
        </a>
    </div>
</div>

打字稿如下:

/// <reference path="knockout.d.ts"/>
/// <reference path="jquery.d.ts" />

module ViewModels {
    export class ItemViewModel {
        public Name: KnockoutObservable<string>;

        constructor(name: string) {
            this.Name = ko.observable(name);
        }//constructor
    }

    export class MainViewModel {
        public SelectedItem: KnockoutObservable<ItemViewModel>;
        public Items: KnockoutComputed<Array<ItemViewModel>>;

        constructor() {
            this.SelectedItem = ko.observable<ItemViewModel>();
            this.Items = ko.computed({
                owner: this,
                read: () => {
                    return this.get_items();
                }
            });
        }

        //TODO: replace this with knockout.mapping plugin transforms
        private …

我有一个ScrollViewer:

<ScrollViewer Width="160" 
              VerticalScrollBarVisibility="Auto" 
              HorizontalScrollBarVisibility="Hidden" 
              Height="324" Canvas.Top="0" 
              BorderThickness="0" Padding="0">
   <ListBox x:Name="Snapshots" SelectionChanged="Snapshots_SelectionChanged" 
            Padding="0" Background="#FFF0F0F0" 
            BorderBrush="{x:Null}" VerticalAlignment="Top" 
            SelectionMode="Single">
      <ItemsControl.ItemTemplate>
         <DataTemplate>
            <Image Source="{Binding imageSource}" 
                   Margin="5" Stretch="UniformToFill" 
                   Width="120" Opacity="0.2"/>
         </DataTemplate>
      </ItemsControl.ItemTemplate>
      <ItemsControl.ItemsPanel>
         <ItemsPanelTemplate>
            <StackPanel Orientation="Vertical"  
                        VerticalAlignment="Top"  HorizontalAlignment="Center"/>
         </ItemsPanelTemplate>
      </ItemsControl.ItemsPanel>
   </ListBox>
</ScrollViewer>

我该如何实现这些功能:

1. 更改所选项目的不透明度(图像).
2. 更改所选项目的默认边框样式(图像).