Xamarin在ListView中更改每个ViewCell的背景色
我在listView中有预约时间,如8:00、9:00等。通过JSON,我从远程数据库检索已经做出的预约。因此,我想将每个单元格(标签)的背景颜色更改为保留的红色,其余的更改为绿色(免费约会) 这是我的xaml代码:Xamarin在ListView中更改每个ViewCell的背景色,listview,xamarin,xamarin.forms,background-color,Listview,Xamarin,Xamarin.forms,Background Color,我在listView中有预约时间,如8:00、9:00等。通过JSON,我从远程数据库检索已经做出的预约。因此,我想将每个单元格(标签)的背景颜色更改为保留的红色,其余的更改为绿色(免费约会) 这是我的xaml代码: <StackLayout> <ListView x:Name="ItemsListView" ItemsSource="{Binding Items}" VerticalOptions="FillAn
<StackLayout>
<ListView x:Name="ItemsListView"
ItemsSource="{Binding Items}"
VerticalOptions="FillAndExpand"
HasUnevenRows="true"
RefreshCommand="{Binding LoadItemsCommand}"
IsPullToRefreshEnabled="true"
IsRefreshing="{Binding IsBusy, Mode=OneWay}"
CachingStrategy="RecycleElement"
ItemSelected="OnItemSelected">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout Padding="10">
<Label Text="{Binding Text}"
LineBreakMode="NoWrap"
Style="{DynamicResource ListItemTextStyle}"
FontSize="16" />
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
那么我怎样才能改变这些细胞的颜色呢
我想要的伪代码:
for(int i=0; i< number of items in the listview; i++) {
if(reservations.contains(listview.itemAt(i)) {
//change background color of viewcell (label?) at position i
}
}
for(int i=0;i
(正如布鲁诺评论的那样)
将IsReserved
布尔属性添加到模型中:
如果IsReserved
为真,则返回Red
的IValueConverter
:
添加IValueConverter的命名空间:
将IValueConverter添加到ContentPage。参考资料
您可以使用自定义视图单元格。我在项目中编写了一个自定义视图单元格,并使用了XFGloss(XFGloss是Xamarin.Forms项目的一个附加组件,用于向标准XF页面和控件类添加新属性)使listView的行丰富多彩。您的listView不会丢失XFGloss的触觉反馈。我使用的自定义viewCell是:
public class MyViewCell : ViewCell
{
private Color BackgroundColor
{
get => CellGloss.GetBackgroundColor(this);
set => CellGloss.SetBackgroundColor(this, value);
}
public Color EvenColor { get; set; }
public Color UnevenColor { get; set; }
protected override void OnAppearing()
{
base.OnAppearing();
if (!(Parent is ListView listView))
throw new Exception(
$"The Binding Context is not {typeof(ListView)}. This component works only with {typeof(ListView)}.");
int index;
if (listView.IsGroupingEnabled)
{
index = listView.TemplatedItems.GetGroupAndIndexOfItem(BindingContext).Item2;
}
else
{
index = listView.TemplatedItems.IndexOf(this);
}
if (index != -1)
BackgroundColor = index % 2 == 0 ? EvenColor : UnevenColor;
}
}
它在xaml文件中的用法很简单,如下所示:
<components:MyViewCell EvenColor="White" UnevenColor="#eeeeee">
如果您更改模型以保留属性,会更容易。例如,在Listview viewcell中,您只需使用一个转换器来更改颜色。我太新手了,无法理解您所说的一半内容。谢谢您提供的详细答案,您的代码显然有效。@ChrisFodor很高兴有什么方法可以代替指定使用IvalueConverter的颜色仅用于将其作为参数传递?例如=IsReserved=true,color red;。要能够将不同的颜色传递给帧?@Pxaml当然,您可以将属性指定为实际颜色(color.red等),或者使用绑定参数并传递颜色:
public class IsReservedToColorConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
return ((bool)value ? Color.Red : Color.Transparent);
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
xmlns:local="clr-namespace:SameNameSpace;assembly=SomeAssemblyName"
<ContentPage.Resources>
<ResourceDictionary>
<local:IsReservedToColorConverter x:Key="IsReservedToColor"></local:IsReservedToColorConverter>
</ResourceDictionary>
</ContentPage.Resources>
<Frame BackgroundColor = "{Binding IsReserved, Converter={StaticResource IsReservedToColor}}">
<?xml version="1.0" encoding="UTF-8"?>
<ContentPage
xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:Class="Forms_31_1.ListPage"
xmlns:local="clr-namespace:Forms_31_1;assembly=Forms_31_1" >
<ContentPage.Resources>
<ResourceDictionary>
<local:IsReservedToColorConverter x:Key="IsReservedToColor"></local:IsReservedToColorConverter>
</ResourceDictionary>
</ContentPage.Resources>
<ContentPage.Content>
<ListView x:Name="listView" BackgroundColor="Aqua" SeparatorColor="Red">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<Frame BackgroundColor = "{Binding IsReserved, Converter={StaticResource IsReservedToColor}}">
<StackLayout Orientation="Vertical">
<Label Text="{Binding Text}" />
<Label Text="{Binding Description}" />
</StackLayout>
</Frame>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</ContentPage.Content>
</ContentPage>
posts.Add(new Termin { Id = Guid.NewGuid().ToString(), Text = "11:00" });
posts.Add(new Termin { Id = Guid.NewGuid().ToString(), Text = "12:00", IsReserved = true });
posts.Add(new Termin { Id = Guid.NewGuid().ToString(), Text = "13:00" });
posts.Add(new Termin { Id = Guid.NewGuid().ToString(), Text = "14:00" });
public class MyViewCell : ViewCell
{
private Color BackgroundColor
{
get => CellGloss.GetBackgroundColor(this);
set => CellGloss.SetBackgroundColor(this, value);
}
public Color EvenColor { get; set; }
public Color UnevenColor { get; set; }
protected override void OnAppearing()
{
base.OnAppearing();
if (!(Parent is ListView listView))
throw new Exception(
$"The Binding Context is not {typeof(ListView)}. This component works only with {typeof(ListView)}.");
int index;
if (listView.IsGroupingEnabled)
{
index = listView.TemplatedItems.GetGroupAndIndexOfItem(BindingContext).Item2;
}
else
{
index = listView.TemplatedItems.IndexOf(this);
}
if (index != -1)
BackgroundColor = index % 2 == 0 ? EvenColor : UnevenColor;
}
}
<components:MyViewCell EvenColor="White" UnevenColor="#eeeeee">