WPF图像控制中的初始图像 [英] initial image in WPF Image Control
本文介绍了WPF图像控制中的初始图像的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
< DataTemplate DataType ={x:Type local:MyData}>
...
< Image Width =50Height =50Source ={Binding Path = profile_image_url_https,FallbackValue = profile_image_url_https}HorizontalAlignment =Left>
...
< / DataTemplate>
解决方案
您可能可以使用 TargetNullValue
绑定,只有在加载时才设置image属性。
例如
< BitmapImage x:Key =DefaultImageUriSource =Images / Error.ico/>
< Image Source = {Binding TestBitmapImage,
TargetNullValue = {StaticResource DefaultImage}}/>
private BitmapImage _TestBitmapImage = null ;
public BitmapImage TestBitmapImage
{
get {return _TestBitmapImage;
set
{
if(_TestBitmapImage!= value)
{
_TestBitmapImage = value;
PropertyChanged.Notify(()=> this.TestBitmapImage);
}
}
}
private void Button_Click(object sender,RoutedEventArgs e)
{
var img = new BitmapImage();
img.DownloadCompleted + =(s,dcea)=>
{
TestBitmapImage = img;
};
img.BeginInit();
img.UriSource = new Uri(http://www.gravatar.com/avatar/c35af79e54306caedad37141f13de30c?s=128&d=identicon&r=PG);
img.EndInit();
}
I have a WPF Image Control in my project that loads from internet (lazy loading), i want to show a initial image in Image Control until main image load. plz help me
<DataTemplate DataType="{x:Type local:MyData}">
...
<Image Width="50" Height="50" Source="{Binding Path=profile_image_url_https, FallbackValue=profile_image_url_https}" HorizontalAlignment="Left">
...
</DataTemplate>
解决方案
You might be able to make it work using TargetNullValue
on the binding, only set the image property when it is loaded.
e.g.
<BitmapImage x:Key="DefaultImage" UriSource="Images/Error.ico" />
<Image Source="{Binding TestBitmapImage,
TargetNullValue={StaticResource DefaultImage}}" />
private BitmapImage _TestBitmapImage = null;
public BitmapImage TestBitmapImage
{
get { return _TestBitmapImage; }
set
{
if (_TestBitmapImage != value)
{
_TestBitmapImage = value;
PropertyChanged.Notify(() => this.TestBitmapImage);
}
}
}
private void Button_Click(object sender, RoutedEventArgs e)
{
var img = new BitmapImage();
img.DownloadCompleted += (s, dcea) =>
{
TestBitmapImage = img;
};
img.BeginInit();
img.UriSource = new Uri("http://www.gravatar.com/avatar/c35af79e54306caedad37141f13de30c?s=128&d=identicon&r=PG");
img.EndInit();
}
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