wpf 设置绑定的边距
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Set a margin from a binding
提问by user589195
I have a binding value that returns a int that represents a value I wasnt to assign to left and right margins of an element.
我有一个绑定值，它返回一个 int 值，该值表示我没有分配给元素的左右边距的值。
Heres what I've tried but it wont compile.
这是我尝试过的，但无法编译。
It works if I set the entire margin, but I only want left and right.
如果我设置整个边距，它会起作用，但我只想要左右。
Xaml:
Xml：
<Image x:Name="_image" Source="mat.png" Margin="{Binding EditorRow.BondIndent},0,{Binding EditorRow.BondIndent},0" />
class:
班级：
public int BondIndent
{
get { return _bondSequence * 5; }
}
回答by Luuk
Return the margin?
退回保证金？
public Thickness Margin
{
get { return new Thickness(BondIndent,0,BondIndent,0);}
}
Then change:
然后改变：
<Image x:Name="_image" Source="mat.png" Margin="{Binding EditorRow.Margin}" />
回答by odyss-jii
You probably need to use a ValueConverterfor this. Something like:
您可能需要为此使用ValueConverter。就像是：
public class LeftRightThicknessConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
if (value is int)
{
int margin = (int)value;
return Thickness(margin, 0, margin, 0);
}
return Thickness();
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
You can then use the converter in the following way:
然后，您可以按以下方式使用转换器：
<Grid>
<Grid.Resources>
<xxx:LeftRightThicknessConverter x:Key="LeftRightThicknessConverter" />
</Grid.Resources>
<Image Margin="{Binding SomePropertyPath, Converter={StaticResource LeftRightThicknessConverter}}" />
</Grid>
Assuming that xxxis a valid xml-namespace.
假设这xxx是一个有效的 xml 命名空间。
回答by Default
Instead of returning an intyou can return a Thickness, which the Marginactually is:
int您可以返回一个Thickness而不是返回一个，它Margin实际上是：
public Thickness BondIndent
{
get
{
int margin = _bondSequence * 5;
return new Thickness(margin, 0, margin, 0);
}
}
The reason why your example works is because Thicknesshas overloaded constructors that take 1, 2 or 4 arguments. Whenthe constructor that takes 1 argument is called, all sides are initialized to that value. WPF automatically converts this to a Thicknessbased on the bound value.
您的示例工作的原因是因为Thickness重载了带有 1、2 或 4 个参数的构造函数。当调用带有 1 个参数的构造函数时，所有边都被初始化为该值。WPFThickness根据绑定值自动将其转换为 a 。
On another topic, BondIndentmight better be called BondMarginor BondThicknessnow.
在另一个主题上，BondIndent最好BondMargin还是BondThickness现在调用。
回答by RandomEngy
Just wrote some attached properties that should make it easy to set an individual Margin value from a binding or static resource:
刚刚编写了一些附加属性，可以轻松地从绑定或静态资源中设置单个 Margin 值：
WPF:
WPF：
public class Margin
{
public static readonly DependencyProperty LeftProperty = DependencyProperty.RegisterAttached(
"Left",
typeof(double),
typeof(Margin),
new PropertyMetadata(0.0, LeftChanged));
private static void LeftChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var frameworkElement = d as FrameworkElement;
if (frameworkElement != null)
{
Thickness currentMargin = frameworkElement.Margin;
frameworkElement.Margin = new Thickness((double)e.NewValue, currentMargin.Top, currentMargin.Right, currentMargin.Bottom);
}
}
public static void SetLeft(UIElement element, double value)
{
element.SetValue(LeftProperty, value);
}
public static double GetLeft(UIElement element)
{
return 0;
}
public static readonly DependencyProperty TopProperty = DependencyProperty.RegisterAttached(
"Top",
typeof(double),
typeof(Margin),
new PropertyMetadata(0.0, TopChanged));
private static void TopChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var frameworkElement = d as FrameworkElement;
if (frameworkElement != null)
{
Thickness currentMargin = frameworkElement.Margin;
frameworkElement.Margin = new Thickness(currentMargin.Left, (double)e.NewValue, currentMargin.Right, currentMargin.Bottom);
}
}
public static void SetTop(UIElement element, double value)
{
element.SetValue(TopProperty, value);
}
public static double GetTop(UIElement element)
{
return 0;
}
public static readonly DependencyProperty RightProperty = DependencyProperty.RegisterAttached(
"Right",
typeof(double),
typeof(Margin),
new PropertyMetadata(0.0, RightChanged));
private static void RightChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var frameworkElement = d as FrameworkElement;
if (frameworkElement != null)
{
Thickness currentMargin = frameworkElement.Margin;
frameworkElement.Margin = new Thickness(currentMargin.Left, currentMargin.Top, (double)e.NewValue, currentMargin.Bottom);
}
}
public static void SetRight(UIElement element, double value)
{
element.SetValue(RightProperty, value);
}
public static double GetRight(UIElement element)
{
return 0;
}
public static readonly DependencyProperty BottomProperty = DependencyProperty.RegisterAttached(
"Bottom",
typeof(double),
typeof(Margin),
new PropertyMetadata(0.0, BottomChanged));
private static void BottomChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var frameworkElement = d as FrameworkElement;
if (frameworkElement != null)
{
Thickness currentMargin = frameworkElement.Margin;
frameworkElement.Margin = new Thickness(currentMargin.Left, currentMargin.Top, currentMargin.Right, (double)e.NewValue);
}
}
public static void SetBottom(UIElement element, double value)
{
element.SetValue(BottomProperty, value);
}
public static double GetBottom(UIElement element)
{
return 0;
}
}
UWP:
UWP：
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;
}
}
Usage:
用法：
<TextBlock Text="Test"
app:Margin.Top="{Binding MyValue}"
app:Margin.Right="{StaticResource MyResource}"
app:Margin.Bottom="20" />
The nice thing is they won't override the other values on the Margin, so you can combine them as well.
好处是它们不会覆盖 Margin 上的其他值，因此您也可以将它们组合起来。
