C# 如何仅在XAML中设置上边距?
我可以在中单独设置边距,但如何在XAML中设置边距,例如,如何设置边距: 伪代码:C# 如何仅在XAML中设置上边距?,c#,wpf,xaml,margins,C#,Wpf,Xaml,Margins,我可以在中单独设置边距,但如何在XAML中设置边距,例如,如何设置边距: 伪代码: <StackPanel Margin.Top="{Binding TopMargin}"> 您不能仅使用绑定定义上边距,因为边距的类型为厚度,而不是依赖项对象。但是,您可以使用一个多值转换器,它需要4个边距值来生成1个厚度对象 转换器: public class ThicknessMultiConverter : IMultiValueConverter { #region IMultiVa
<StackPanel Margin.Top="{Binding TopMargin}">
您不能仅使用绑定定义上边距,因为
边距
的类型为厚度
,而不是依赖项对象。但是,您可以使用一个多值转换器
,它需要4个边距值来生成1个厚度对象
转换器:
public class ThicknessMultiConverter : IMultiValueConverter
{
#region IMultiValueConverter Members
public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
double left = System.Convert.ToDouble(values[0]);
double top = System.Convert.ToDouble(values[1]);
double right = System.Convert.ToDouble(values[2]);
double bottom = System.Convert.ToDouble(values[3]);
return new Thickness(left, top, right, bottom);
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
{
Thickness thickness = (Thickness)value;
return new object[]
{
thickness.Left,
thickness.Top,
thickness.Right,
thickness.Bottom
};
}
#endregion
}
XAML:
<StackPanel>
<StackPanel.Margin>
<MultiBinding Converter="{StaticResource myThicknessConverter}">
<Binding Path="LeftMargin"/>
<Binding Path="TopMargin"/>
<Binding Path="RightMargin"/>
<Binding Path="BottomMargin"/>
</MultiBinding>
</StackPanel.Margin>
</StackPanel>
使用转换器,下面的示例代码将把绑定到的双精度转换为厚度。它将厚度的“顶部”设置为绑定字段。您可以选择使用ConverterParameter来确定是绑定到左侧、顶部、右侧还是底部
<StackPanel Margin="{Binding TopMargin, Converter={StaticResource MyThicknessConverter}">
关键是要意识到在代码中设置它如下:
sp2.Margin = new System.Windows.Thickness{ Left = 5 };
local:Nifty.Margin="H000"
public class ItemViewModel
{
public Thickness Margin { get; private set }
public ItemViewModel(ModelClass model)
{
/// You can calculate needed margin here,
/// probably depending on some value from the Model
this.Margin = new Thickness(0,model.TopMargin,0,0);
}
}
相当于:
sp2.Margin = new System.Windows.Thickness{ Left = 5, Top = 0, Right = 0, Bottom = 0 };
不能通过代码或XAML在Thickness
实例中仅设置一个值。如果不设置某些值,它们将隐式为零。因此,您可以这样做,将另一个问题中接受的代码示例转换为XAML等效代码:
<StackPanel Margin="{Binding TopMargin, Converter={StaticResource MyConverter}}"/>
与自定义控件相比,更好的选择是编写附加属性,并使用依赖属性设置器中的上述代码更改厚度。下面的代码可用于所有有余量的控件
public static readonly DependencyProperty TopMarginProperty =
DependencyProperty.RegisterAttached("TopMargin", typeof(int), typeof(FrameworkElement),
new FrameworkPropertyMetadata(false, FrameworkPropertyMetadataOptions.AffectsRender));
public static void SetTopMargin(FrameworkElement element, int value)
{
// set top margin in element.Margin
}
public static int GetTopMargin(FrameworkElement element)
{
// get top margin from element.Margin
}
如果您将此与行为相结合,您可以在TopMargin属性上获得通知更改。这不是您要寻找的吗
<StackPanel Margin="0,10,0,0" />
第一个值是左边距,然后是上边距,然后是右边距,最后是下边距
我不确定您是否要将其绑定到某个对象,但如果不想,那就行了。我想您可以使用属性语法,从:
这样你就不需要任何转换器了
但是顶部不是dependencProperty-返回到转换器(back-to-converter)最好是通过指定类似下面的代码示例的内容来实现这一点
<StackPanel Margin=",10,,">
不幸的是,WPF中默认情况下似乎不存在此功能,这是一个遗憾,因为它要求开发人员硬编码已知的默认值,这样以后就更难对应用程序进行蒙皮或主题化
目前我能想到的最好的解决方案是使用转换器,但引入转换器所需的额外代码量并不理想。这里有一个很好的解决方案:
public class Nifty
{
private static double _tiny;
private static double _small;
private static double _medium;
private static double _large;
private static double _huge;
private static bool _resourcesLoaded;
#region Margins
public static readonly DependencyProperty MarginProperty =
DependencyProperty.RegisterAttached("Margin", typeof(string), typeof(Nifty),
new PropertyMetadata(string.Empty,
new PropertyChangedCallback(OnMarginChanged)));
public static Control GetMargin(DependencyObject d)
{
return (Control)d.GetValue(MarginProperty);
}
public static void SetMargin(DependencyObject d, string value)
{
d.SetValue(MarginProperty, value);
}
private static void OnMarginChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
FrameworkElement ctrl = d as FrameworkElement;
if (ctrl == null)
return;
string Margin = (string)d.GetValue(MarginProperty);
ctrl.Margin = ConvertToThickness(Margin);
}
private static Thickness ConvertToThickness(string Margin)
{
var result = new Thickness();
if (!_resourcesLoaded)
{
_tiny = (double)Application.Current.FindResource("TinySpace");
_small = (double)Application.Current.FindResource("SmallSpace");
_medium = (double)Application.Current.FindResource("MediumSpace");
_large = (double)Application.Current.FindResource("LargeSpace");
_huge = (double)Application.Current.FindResource("HugeSpace");
_resourcesLoaded = true;
}
result.Left = CharToThickness(Margin[0]);
result.Top = CharToThickness(Margin[1]);
result.Bottom = CharToThickness(Margin[2]);
result.Right = CharToThickness(Margin[3]);
return result;
}
private static double CharToThickness(char p)
{
switch (p)
{
case 't':
case 'T':
return _tiny;
case 's':
case 'S':
return _small;
case 'm':
case 'M':
return _medium;
case 'l':
case 'L':
return _large;
case 'h':
case 'H':
return _huge;
default:
return 0.0;
}
}
#endregion
}
如果将此代码添加到命名空间并定义以下大小:
<system:Double x:Key="TinySpace">2</system:Double>
<system:Double x:Key="SmallSpace">5</system:Double>
<system:Double x:Key="MediumSpace">10</system:Double>
<system:Double x:Key="LargeSpace">20</system:Double>
<system:Double x:Key="HugeSpace">20</system:Double>
或
代码将根据您的资源创建边距。这属于WPF修订:
sp2.Margin = new System.Windows.Thickness{ Left = 5 };
local:Nifty.Margin="H000"
public class ItemViewModel
{
public Thickness Margin { get; private set }
public ItemViewModel(ModelClass model)
{
/// You can calculate needed margin here,
/// probably depending on some value from the Model
this.Margin = new Thickness(0,model.TopMargin,0,0);
}
}
然后XAML很简单:
<StackPanel Margin="{Binding Margin}">
这里有一种简单的方法,可以在不编写转换器或硬编码边距值的情况下执行此操作。首先,在窗口(或其他控件)资源中定义以下内容:
<Window.Resources>
<!-- Define the default amount of space -->
<system:Double x:Key="Space">10.0</system:Double>
<!-- Border space around a control -->
<Thickness
x:Key="BorderSpace"
Left="{StaticResource Space}"
Top="{StaticResource Space}"
Right="{StaticResource Space}"
Bottom="{StaticResource Space}"
/>
<!-- Space between controls that are positioned vertically -->
<Thickness
x:Key="TopSpace"
Top="{StaticResource Space}"
/>
</Window.Resources>
现在,如果要更改控件之间的默认间距,只需在一个位置进行更改。刚刚编写了一些附加属性,这些属性可以轻松地从绑定或静态资源设置单个边距值:
public class Margin
{
public static readonly DependencyProperty LeftProperty = DependencyProperty.RegisterAttached(
"Left",
typeof(double),
typeof(Margin),
new PropertyMetadata(0.0));
public static void SetLeft(UIElement element, double value)
{
var frameworkElement = element as FrameworkElement;
if (frameworkElement != null)
{
Thickness currentMargin = frameworkElement.Margin;
frameworkElement.Margin = new Thickness(value, currentMargin.Top, currentMargin.Right, currentMargin.Bottom);
}
}
public static double GetLeft(UIElement element)
{
return 0;
}
public static readonly DependencyProperty TopProperty = DependencyProperty.RegisterAttached(
"Top",
typeof(double),
typeof(Margin),
new PropertyMetadata(0.0));
public static void SetTop(UIElement element, double value)
{
var frameworkElement = element as FrameworkElement;
if (frameworkElement != null)
{
Thickness currentMargin = frameworkElement.Margin;
frameworkElement.Margin = new Thickness(currentMargin.Left, value, currentMargin.Right, currentMargin.Bottom);
}
}
public static double GetTop(UIElement element)
{
return 0;
}
public static readonly DependencyProperty RightProperty = DependencyProperty.RegisterAttached(
"Right",
typeof(double),
typeof(Margin),
new PropertyMetadata(0.0));
public static void SetRight(UIElement element, double value)
{
var frameworkElement = element as FrameworkElement;
if (frameworkElement != null)
{
Thickness currentMargin = frameworkElement.Margin;
frameworkElement.Margin = new Thickness(currentMargin.Left, currentMargin.Top, value, currentMargin.Bottom);
}
}
public static double GetRight(UIElement element)
{
return 0;
}
public static readonly DependencyProperty BottomProperty = DependencyProperty.RegisterAttached(
"Bottom",
typeof(double),
typeof(Margin),
new PropertyMetadata(0.0));
public static void SetBottom(UIElement element, double value)
{
var frameworkElement = element as FrameworkElement;
if (frameworkElement != null)
{
Thickness currentMargin = frameworkElement.Margin;
frameworkElement.Margin = new Thickness(currentMargin.Left, currentMargin.Top, currentMargin.Right, value);
}
}
public static double GetBottom(UIElement element)
{
return 0;
}
}
用法:
<TextBlock Text="Test"
app:Margin.Top="{Binding MyValue}"
app:Margin.Right="{StaticResource MyResource}"
app:Margin.Bottom="20" />
在UWP中进行了测试,但这适用于任何基于XAML的框架。好在它们不会覆盖边距上的其他值,因此您也可以将它们组合起来。我使用绑定到边距的值转换器(RelativeSource Self)并解析转换器参数,如“top:123;left:456”所示 转换器仅覆盖参数给定的边距
public class MarginConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
if (!(value is Thickness)) return new Thickness();
Thickness retMargin = (Thickness) value;
List<string> singleMargins = (parameter as string)?.Split(';').ToList() ?? new List<string>();
singleMargins.ForEach(m => {
switch (m.Split(':').ToList()[0].ToLower().Trim()) {
case "left":
retMargin.Left = double.Parse(m.Split(':').ToList()[1].Trim());
break;
case "top":
retMargin.Top = double.Parse(m.Split(':').ToList()[1].Trim());
break;
case "right":
retMargin.Right = double.Parse(m.Split(':').ToList()[1].Trim());
break;
case "bottom":
retMargin.Bottom = double.Parse(m.Split(':').ToList()[1].Trim());
break;
}
}
);
return retMargin;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
公共类MarginConverter:IValueConverter
{
公共对象转换(对象值、类型targetType、对象参数、CultureInfo区域性)
{
如果(!(值为厚度))返回新厚度();
厚度边缘=(厚度)值;
List singleMargins=(参数为字符串)?.Split(“;”).ToList()?new List();
singleMargins.ForEach(m=>{
开关(m.Split(“:”).ToList()[0].ToLower().Trim()){
案例“左”:
retMargin.Left=double.Parse(m.Split(“:”).ToList()[1].Trim());
打破
案例“顶部”:
retMargin.Top=double.Parse(m.Split(“:”).ToList()[1].Trim());
打破
案例“权利”:
retMargin.Right=double.Parse(m.Split(':').ToList()[1].Trim());
打破
案例“底部”:
retMargin.Bottom=double.Parse(m.Split(“:”).ToList()[1].Trim());
打破
<TextBlock Text="Test"
app:Margin.Top="{Binding MyValue}"
app:Margin.Right="{StaticResource MyResource}"
app:Margin.Bottom="20" />
public class MarginConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
if (!(value is Thickness)) return new Thickness();
Thickness retMargin = (Thickness) value;
List<string> singleMargins = (parameter as string)?.Split(';').ToList() ?? new List<string>();
singleMargins.ForEach(m => {
switch (m.Split(':').ToList()[0].ToLower().Trim()) {
case "left":
retMargin.Left = double.Parse(m.Split(':').ToList()[1].Trim());
break;
case "top":
retMargin.Top = double.Parse(m.Split(':').ToList()[1].Trim());
break;
case "right":
retMargin.Right = double.Parse(m.Split(':').ToList()[1].Trim());
break;
case "bottom":
retMargin.Bottom = double.Parse(m.Split(':').ToList()[1].Trim());
break;
}
}
);
return retMargin;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
<TextBlock Margin="{Binding RelativeSource={RelativeSource Self},
Path=Margin,
Converter={StaticResource MarginConverter},
ConverterParameter='top:0'}"
Style="{StaticResource Header}"
Text="My Header" />