如何在 Silverlight 2 MultiScaleImage 物件拖放

註: 這裡的範例程式碼是針對 Silverlight 2 Beta1, 在 beta2 中, MultiScaleImage 的 Source 的型態有些改變。

Silverlight 2 的一些範例如: Hardrock (https://memorial.hardrock.com/), 故宮清明上河圖 (https://learnet.npm.gov.tw/silverlight/) 都使用到滑鼠拖放圖片, 這是一個常用的功能, 因為常被問到, 所以把相關程式碼提供出來讓大家參考:

Page.xaml

<UserControl x:Class="SilverlightApplication3.Page"
    xmlns="https://schemas.microsoft.com/client/2007"
    xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml"
    >

    <Grid x:Name="LayoutRoot" Background="White">
        <MultiScaleImage x:Name="dz"
            Source="deepzoomtest1/info.bin" UseSprings="False"
                         MouseLeftButtonDown="MultiScaleImage_MouseLeftButtonDown"
                         MouseMove="MultiScaleImage_MouseMove"
                         MouseLeftButtonUp="MultiScaleImage_MouseLeftButtonUp"
                         />
    </Grid>
</UserControl>

Page.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace SilverlightApplication3
{
    public partial class Page : UserControl
    {
        public Page() {
            InitializeComponent();
        }

    public partial class Page : UserControl
    {

        bool dragging = false;
        Point dragOffset;
        Point currentPosition;

        private void MultiScaleImage_MouseLeftButtonDown(object sender, MouseButtonEventArgs e) {
            dragging = true;
            dragOffset = e.GetPosition(this);
            currentPosition = dz.ViewportOrigin;
        }

        private void MultiScaleImage_MouseMove(object sender, MouseEventArgs e) {
            if (dragging) {
                Point newOrigin = new Point();
                Point pMouse = e.GetPosition(this); 
                double ratio = dz.ViewportWidth / dz.ActualWidth;
                newOrigin.X = currentPosition.X - (pMouse.X - dragOffset.X) * ratio;
                newOrigin.Y = currentPosition.Y - (pMouse .Y - dragOffset.Y) * ratio;
                dz.ViewportOrigin = newOrigin;
            }
        }

        private void MultiScaleImage_MouseLeftButtonUp(object sender, MouseButtonEventArgs e) {
            dragging = false;
        }

    }

}