如何将值传递并设置为Usercontrol。
这里有两个关于WPF项目的问题。
概述： 在这个项目中，我尝试将Usercontrol用作画布上的资源，并通过LineGeometry将它们相互连接。 ＆＃39; MyThumb＆＃39; class i用于控制可拖动和控制设置值。 我正在使用覆盖的OnApplyTemplate＆＃39;在Usercontrol上传递值的方法。要使用＆＃39; Template.FindName＆＃39;来设置值。这里它返回null。 现在的问题是如何在usercontrol＆＃39;上设置值。在下面的代码中：
另一个问题与线条颜色有关。在项目中，我使用LineGeometry在用户控件之间显示行但不能更改行颜色..想要设置不同颜色的不同行。 这里的问题是如何改变现有LineGeometry的颜色。
请查看我使用的代码：
Mythumb.cs
public class MyThumb : Thumb
{
#region Properties
public static readonly DependencyProperty TitleProperty = DependencyProperty.Register("Title", typeof(string), typeof(MyThumb), new UIPropertyMetadata(""));
public static readonly DependencyProperty ImageSourceProperty = DependencyProperty.Register("ImageSource", typeof(string), typeof(MyThumb), new UIPropertyMetadata(""));
// This property will hanlde the content of the textblock element taken from control template
public string Title
{
get { return (string)GetValue(TitleProperty); }
set { SetValue(TitleProperty, value); }
}
// This property will handle the content of the image element taken from control template
public string ImageSource
{
get { return (string)GetValue(ImageSourceProperty); }
set { SetValue(ImageSourceProperty, value); }
}
public Point MyLocation
{
get
{
Point nm = new Point(Canvas.GetLeft(this), Canvas.GetTop(this));
return nm;
}
}
public List<LineGeometry> EndLines { get; private set; }
public List<LineGeometry> StartLines { get; private set; }
#endregion
#region Constructors
public MyThumb()
: base()
{
StartLines = new List<LineGeometry>();
EndLines = new List<LineGeometry>();
}
public MyThumb(string title, string imageSource, Point position)
: this()
{
//Setting ControlTemplate as Usercontrol 'ContactNode'
ControlTemplate templatex = new ControlTemplate();
var fec = new FrameworkElementFactory(typeof(ContactNode));
templatex.VisualTree = fec;
this.Template = templatex;
this.Title = (title != null) ? title : string.Empty;
this.ImageSource = (imageSource != null) ? imageSource : string.Empty;
this.SetPosition(position);
}
public MyThumb( string title, string imageSource, Point position, DragDeltaEventHandler dragDelta)
: this(title, imageSource, position)
{
this.DragDelta += dragDelta;
}
#endregion
// Helper method for setting the position of our thumb
public void SetPosition(Point value)
{
Canvas.SetLeft(this, value.X);
Canvas.SetTop(this, value.Y);
}
#region Linking logic
// This method establishes a link between current thumb and specified thumb.
// Returns a line geometry with updated positions to be processed outside.
public LineGeometry LinkTo(MyThumb target)
{
// Create new line geometry
LineGeometry line = new LineGeometry();
// Save as starting line for current thumb
this.StartLines.Add(line);
// Save as ending line for target thumb
target.EndLines.Add(line);
// Ensure both tumbs the latest layout
this.UpdateLayout();
target.UpdateLayout();
// Update line position
line.StartPoint = new Point(Canvas.GetLeft(this) + this.ActualWidth / 2, Canvas.GetTop(this) + this.ActualHeight / 2);
line.EndPoint = new Point(Canvas.GetLeft(target) + target.ActualWidth / 2, Canvas.GetTop(target) + target.ActualHeight / 2);
// return line for further processing
return line;
}
// This method establishes a link between current thumb and target thumb using a predefined line geometry
// Note: this is commonly to be used for drawing links with mouse when the line object is predefined outside this class
public bool LinkTo(MyThumb target, LineGeometry line)
{
// Save as starting line for current thumb
this.StartLines.Add(line);
// Save as ending line for target thumb
target.EndLines.Add(line);
// Ensure both tumbs the latest layout
this.UpdateLayout();
target.UpdateLayout();
// Update line position
line.StartPoint = new Point(Canvas.GetLeft(this) + this.ActualWidth / 2, Canvas.GetTop(this) + this.ActualHeight / 2);
line.EndPoint = new Point(Canvas.GetLeft(target) + target.ActualWidth / 2, Canvas.GetTop(target) + target.ActualHeight / 2);
return true;
}
#endregion
// This method updates all the starting and ending lines assigned for the given thumb
// according to the latest known thumb position on the canvas
public void UpdateLinks()
{
double left = Canvas.GetLeft(this);
double top = Canvas.GetTop(this);
for (int i = 0; i < this.StartLines.Count; i++)
this.StartLines[i].StartPoint = new Point(left + this.ActualWidth / 2, top + this.ActualHeight / 2);
for (int i = 0; i < this.EndLines.Count; i++)
this.EndLines[i].EndPoint = new Point(left + this.ActualWidth / 2, top + this.ActualHeight / 2);
}
// Upon applying template we apply the "Title" and "ImageSource" properties to the template elements.
public override void OnApplyTemplate()
{
base.OnApplyTemplate();
// Access the textblock element of template and assign it if Title property defined
if (this.Title != string.Empty)
{
TextBlock txt = this.Template.FindName("tplTextBlock", this) as TextBlock;
if (txt != null) //getting null here unable to find element..
txt.Text = Title;
}
// Access the image element of our custom template and assign it if ImageSource property defined
if (this.ImageSource != string.Empty)
{
Image img = this.Template.FindName("tplImage", this) as Image;
if (img != null)
img.Source = new BitmapImage(new Uri(this.ImageSource, UriKind.Relative));
}
}
}
Window1.xaml.cs
public partial class Window1 : Window
{
// flag for enabling "New thumb" mode
bool isAddNewAction = false;
// flag for enabling "New link" mode
bool isAddNewLink = false;
// flag that indicates that the link drawing with a mouse started
bool isLinkStarted = false;
// variable to hold the thumb drawing started from
MyThumb linkedThumb;
// Line drawn by the mouse before connection established
LineGeometry link;
public Window1()
{
InitializeComponent();
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
Point pp = new Point(myCanvas.ActualWidth/2,myCanvas.ActualHeight/2);
AdNewNode(pp, "ACTION", "/Images/gear_connection.png");
this.PreviewMouseLeftButtonDown += new MouseButtonEventHandler(Window1_PreviewMouseLeftButtonDown);
this.PreviewMouseMove += new MouseEventHandler(Window1_PreviewMouseMove);
this.PreviewMouseLeftButtonUp += new MouseButtonEventHandler(Window1_PreviewMouseLeftButtonUp);
}
// Event hanlder for dragging functionality support
private void onDragDelta(object sender, System.Windows.Controls.Primitives.DragDeltaEventArgs e)
{
// Exit dragging operation during adding new link
if (isAddNewLink) return;
MyThumb thumb = e.Source as MyThumb;
Canvas.SetLeft(thumb, Canvas.GetLeft(thumb) + e.HorizontalChange);
Canvas.SetTop(thumb, Canvas.GetTop(thumb) + e.VerticalChange);
// Update links' layouts for active thumb
thumb.UpdateLinks();
}
// Event handler for creating new thumb element by left mouse click
// and visually connecting it to the myThumb2 element
void AdNewNode(Point nPosition,string nTitle, string nImage)
{
MyThumb newThumb = new MyThumb(
nTitle,
nImage,
nPosition,
onDragDelta);
myCanvas.Children.Add(newThumb);
}
void Window1_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
// If adding new action...
if (isAddNewAction)
{
AdNewNode(e.GetPosition(this), "ACTION", "/Images/gear_connection.png");
// resume common layout for application
isAddNewAction = false;
Mouse.OverrideCursor = null;
btnNewAction.IsEnabled = btnNewLink.IsEnabled = true;
e.Handled = true;
}
// Is adding new link and a thumb object is clicked...
if (isAddNewLink && e.Source.GetType() == typeof(MyThumb))
{
if (!isLinkStarted)
{
if (link == null || link.EndPoint != link.StartPoint)
{
Point position = e.GetPosition(this);
link = new LineGeometry(position, position);
//nodepath=new Path();
//nodepath.Stroke = Brushes.Pink;
//nodepath.Data = link; // Here line color is getting change but connectivity getting lost....
connectors.Children.Add(link);
//myCanvas.Children.Add(nodepath);
isLinkStarted = true;
linkedThumb = e.Source as MyThumb;
e.Handled = true;
}
}
}
}
// Handles the mouse move event when dragging/drawing the new connection link
void Window1_PreviewMouseMove(object sender, MouseEventArgs e)
{
if (isAddNewLink && isLinkStarted)
{
// Set the new link end point to current mouse position
link.EndPoint = e.GetPosition(this);
e.Handled = true;
}
}
// Handles the mouse up event applying the new connection link or resetting it
void Window1_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
// If "Add link" mode enabled and line drawing started (line placed to canvas)
if (isAddNewLink && isLinkStarted)
{
// declare the linking state
bool linked = false;
// We released the button on MyThumb object
if (e.Source.GetType() == typeof(MyThumb))
{
MyThumb targetThumb = e.Source as MyThumb;
// define the final endpoint of line
link.EndPoint = e.GetPosition(this);
// if any line was drawn (avoid just clicking on the thumb)
if (link.EndPoint != link.StartPoint && linkedThumb != targetThumb)
{
// establish connection
linkedThumb.LinkTo(targetThumb, link);
// set linked state to true
//nodepath = new Path();
//nodepath.Stroke = Brushes.Pink;
//nodepath.Data = link;
linked = true;
}
}
// if we didn't manage to approve the linking state
// button is not released on MyThumb object or double-clicking was performed
if (!linked)
{
// remove line from the canvas
//connectors.Children.Remove(link);
// clear the link variable
link = null;
}
// exit link drawing mode
isLinkStarted = isAddNewLink = false;
// configure GUI
btnNewAction.IsEnabled = btnNewLink.IsEnabled = true;
Mouse.OverrideCursor = null;
e.Handled = true;
}
//this.Title = "Links established: " + connectors.Children.Count.ToString();
}
// Event handler for enabling new thumb creation by left mouse button click
private void btnNewAction_Click(object sender, RoutedEventArgs e)
{
isAddNewAction = true;
Mouse.OverrideCursor = Cursors.SizeAll;
btnNewAction.IsEnabled = btnNewLink.IsEnabled = false;
}
private void btnNewLink_Click(object sender, RoutedEventArgs e)
{
isAddNewLink = true;
Mouse.OverrideCursor = Cursors.Cross;
btnNewAction.IsEnabled = btnNewLink.IsEnabled = false;
}
}
请尝试纠正我在此代码中出错的地方。