C# WPF后台动态添加控件(经典)

语言: CN / TW / HK

概述

在Winform中从后台添加控件相对比较容易,但是在WPF中,我们知道界面是通过XAML编写的,如何把后台写好的控件动态添加到前台呢?本节举例介绍这个问题。

这里要用到UniformGrid布局,UniformGrid 是一种横向的网格分割、纵向的网格分割分别是均等的分割的布局类型.

项目介绍

-. 这里界面添加一个ComboBox用来下拉选择图片数量;

-. 添加一个button用来执行图片显示;

dispaly下方是图片显示区域

代码设计

-.前台XAML代码:

<Grid>
        <dxlc:LayoutControl Orientation="Vertical">
            <dxlc:LayoutGroup Orientation="Horizontal" View="GroupBox">
                <dxlc:LayoutGroup.Header>
                    <dxlc:LayoutItem Label="Action" Background="#FF004486" Foreground="White"/>
                </dxlc:LayoutGroup.Header>
                <dxlc:LayoutItem Label="Image Count" >
                    <ComboBox SelectedIndex="{Binding ComSelectedIndex}">
                        <ComboBoxItem>2</ComboBoxItem>
                        <ComboBoxItem>4</ComboBoxItem>
                        <ComboBoxItem>6</ComboBoxItem>
                    </ComboBox>
                </dxlc:LayoutItem>
                <dxlc:LayoutItem Width="110">
                    <dx:SimpleButton Content="Image Dispaly" Background="LightGray" 
                       cal:Message.Attach="[Event Click]=[btnAdd_Click($source,$eventArgs)]" />
                </dxlc:LayoutItem>
            </dxlc:LayoutGroup>

            <dxlc:LayoutGroup Orientation="Horizontal" View="GroupBox">
                <dxlc:LayoutGroup.Header>
                    <dxlc:LayoutItem Label="Dispaly" Background="#FF004486" Foreground="White"/>
                </dxlc:LayoutGroup.Header>
                <UniformGrid 
                        cal:Message.Attach="[Event Loaded]=[UniformGrid_Loaded($source,$eventArgs)]" />
            </dxlc:LayoutGroup>
        </dxlc:LayoutControl>
    </Grid>

前台代码比较简单,只要关注下UniformGrid控件,绑定了Loaded事件。

-.后台代码:

[AddINotifyPropertyChangedInterface]
    public class UniformGridViewModel : Screen, IViewModel
    {
        public int ComSelectedIndex { get; set; }

        public UniformGrid UniformGrid;

        public string[] ImageFullPath;
        public void btnAdd_Click(object sender, RoutedEventArgs e)
        {

            UniformGrid.Children.Clear();
            UniformGrid.Columns = 2;

            var count = 0;
            switch(ComSelectedIndex)
            {
                case 0:
                    count = 2;break;
                case 1:
                    count = 4; break;
                case 2:
                    count = 6; break;
                default: break;
            }
            for (int i = 0; i < count; i++)
            {
                Image image = new Image();
                image.Source = LoadImageFreeze(ImageFullPath[i]);
                image.MouseLeftButtonUp += ImageClick;
                image.Name = Path.GetFileNameWithoutExtension(ImageFullPath[i]);
                image.Margin = new Thickness(5);
                UniformGrid.Children.Add(image);
            }
        }

        public void ImageClick(object sender, MouseButtonEventArgs e)
        {
            var name = (sender as Image).Name;
            MessageBox.Show($"当前选择的图片名称:{name}");
        }
        public void UniformGrid_Loaded(object sender, RoutedEventArgs e)
        {
            UniformGrid = (UniformGrid)sender;
        }
        public UniformGridViewModel()
        {
            DisplayName = "UniformGrid";
            string imagePath =Path.Combine( AppDomain.CurrentDomain.BaseDirectory, "Images");
            ImageFullPath = Directory.GetFiles(imagePath, "*.png");
        }

        public static BitmapImage LoadImageFreeze(string imagePath)
        {
            try
            {
                var bitmap = new BitmapImage();
                if (File.Exists(imagePath))
                {
                    bitmap.BeginInit();
                    bitmap.CacheOption = BitmapCacheOption.OnLoad;

                    using (Stream ms = new MemoryStream(File.ReadAllBytes(imagePath)))
                    {
                        bitmap.StreamSource = ms;
                        bitmap.EndInit();
                        bitmap.Freeze();
                    }
                }
                return bitmap;
            }
            catch (Exception)
            {
                return null;
            }
        }
    }

介绍:

①LoadImageFreeze:从路径下加载图片并转换为BitmapImage;

②UniformGrid_Loaded;获取UniformGrid对象;

③ImageFullPath:从项目bin下获取图片文件并读取到这个数组;

④btnAdd_Click:界面button点击事件,这里是核心的代码,主要就是申城图片,然后设定好  UniformGrid的行列以及其他属性后添加到控件里面,  UniformGrid.Children.Add(image);

⑤ImageClick:点击后显示图片的名称.

源码

百度网盘链接:https://pan.baidu.com/s/1iu2MovTGDoUd_HsTnI7mAA

提取码:6666

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