C＃wpf中的画布处理 [英] Canvas handling in C# wpf

问题描述

您好

任何人都可以帮助我一次如何选择多个帆布儿童



谢谢

Maheshwar

Hi
can anyone please help me on how to select multiple canvas children at a time

Thank you
Maheshwar

推荐答案

hi
问题是我在画布上有图像，我想在点击和拖动时选择图像...出于同样的目的，我使用了两个画布...

1.画布所在的画布（.png格式）

2.画布用于点击并拖动。



这里的代码是相同的



/////// ////////////////////////////////////////////////// ///////代码///////////////////////////

XAML;





< grid x：name =theGridxmlns：x =＃unknown>

MouseDown = Grid_MouseDown

MouseUp =Grid_MouseUp

MouseMove =Grid_MouseMove

背景=透明

> ; <！---->

< canvas name =myCanvashorizo​​ntalalignment =Centerverticalalignment =Stretchallowdrop =Truedrop =DropImagemouserightbuttondown =myCanvas_MouseRightButtonDown_1 width =648margin =9,9,9,7grid.column =1grid.row =3>

<！---->

< image margin =2,0,0,10name =imgPhotomouseleftbuttondown =DragImageallowdrop =Truemouserightbuttondown =Image_MouseRightButtonDown_1>

Stretch =填充Grid.Row =1Grid.ColumnSpan =4Grid.Column =1Grid.RowSpan =2/>



< canvas.contextmenu>

< contextmenu foreground =White>

< menuitem header =删除click =Delete1>

< menuitem header =Clear Canvasclick =CLEAR_EVENT1>

< menuitem header =newclick =new_session>

< menuitem header =copycommand =ApplicationCommands.Copy>

< menuitem header =pastecommand =ApplicationCommands.Paste>



< /canvas.contextmenu>

<！---->





<！---->

< canvas>

<！ - 这个画布覆盖在上一个画布上，用于

放置实现拖动选择框的矩形。 - >

< rectangle>

x：Name =selectionBox

可见性=折叠

Stroke =Black

StrokeThickness =1

/>

< / canvas>

<！---->





XAML.cs



bool mouseDown = false; //按住鼠标时设置为true。

Point mouseDownPos; //单击鼠标按钮的位置。



private void Grid_MouseDown（object sender，MouseButtonEventArgs e）

{

//捕获并跟踪鼠标。

mouseDown = true;

mouseDownPos = e.GetPosition（theGrid）;

theGrid.CaptureMouse（）;



//拖动选择框的初始位置。

Canvas.SetLeft（selectionBox，mouseDownPos.X）;

Canvas.SetTop（selectionBox，mouseDownPos.Y）;

selectionBox.Width = 0;

selectionBox.Height = 0;



//使拖动选择框可见。

selectionBox .Visibility = Visibility.Visible;

myCanvas.Children.Contains（selectedElement）;

}



private void Grid_MouseUp（object sender，MouseButtonEventArgs e）

{

//释放鼠标捕获并停止跟踪它。

mouseDown = false;

theGrid.ReleaseMouseCapture（）;



//隐藏拖动选择框。

selectionBox.Visibility = Visibility .Claplapsed;



Point mouseUpPos = e.GetPosition（theGrid）;




}



private void Grid_MouseMove（object sender，System.Windows.Input.MouseEventArgs e）

{

if（mouseDown）

{



//按住鼠标时，重新定位拖动选择框。



Point mousePos = e.GetPosition（theGrid）;



if（mouseDownPos.X< mousePos.X）

{

Canvas.SetLeft（selectionBox，mouseDownPos.X）;

selectionBox.Width = mousePos.X - mouseDownPos。 X;

}

其他

{

Canvas.SetLeft（selectionBox，mousePos.X）;

selectionBox.Width = mouseDownPos.X - mousePos.X;

}



if（mouseDownPos.Y< mousePos.Y）

{

Canvas.SetTop（selectionBox，mouseDownPos.Y）;

selectionBox.Height = mousePos.Y - mouseDownPos。 Y;

}

其他

{

Canvas.SetTop（selectionBox，mousePos.Y）;

selectionBox.Height = mouseDownPos.Y - mousePos.Y;

}



myCanvas.Children.Contains（selectedElement）;



if（selected）

{

selected = false;

if（selectedElement！= null）

{

/ /从所选元素中删除装饰器



//<<我已经在添加删除按钮后证明了这一点，因为adorner layer issue>>



aLayer.Remove（aLayer.GetAdorners（selectedElement）[0]）;

selectedElement = null;

}

}





if（e.Source！= myCanvas）

{

_isDown = true;

_startPoint = e.GetPosition（myCan vas）;



selectedElement = e.Source as UIElement;



_originalLeft = Canvas.GetLeft（selectedElement ）;

_originalTop = Canvas.GetTop（selectedElement）;



aLayer = AdornerLayer.GetAdornerLayer（selectedElement）;



aLayer.Add（new ResizingAdorner（selectedElement））;

selected = true;

e.Handled = true;



}

}

}

hi The problem is i have a images on the canvas and i want to select the images on click and drag... for the same purpose i have used two canvas...
1. the canvas on which images are there (.png format)
2. the canvas which is used for click and drag.

here i s the code for the same

////////////////////////////////////////////////////////////////Code///////////////////////////
XAML;


<grid x:name="theGrid" xmlns:x="#unknown">
MouseDown="Grid_MouseDown"
MouseUp="Grid_MouseUp"
MouseMove="Grid_MouseMove"
Background="Transparent"
> <!---->
<canvas name="myCanvas" horizontalalignment="Center" verticalalignment="Stretch" allowdrop="True" drop="DropImage" mouserightbuttondown="myCanvas_MouseRightButtonDown_1" width="648" margin="9,9,9,7" grid.column="1" grid.row="3">
<!---->
<image margin="2,0,0,10" name="imgPhoto" mouseleftbuttondown="DragImage" allowdrop="True" mouserightbuttondown="Image_MouseRightButtonDown_1">
Stretch="Fill" Grid.Row="1" Grid.ColumnSpan="4" Grid.Column="1" Grid.RowSpan="2" />

<canvas.contextmenu>
<contextmenu foreground="White">
<menuitem header="Delete" click="Delete1">
<menuitem header="Clear Canvas" click="CLEAR_EVENT1">
<menuitem header="new" click="new_session">
<menuitem header="copy" command="ApplicationCommands.Copy">
<menuitem header="paste" command="ApplicationCommands.Paste">

</canvas.contextmenu>
<!---->


<!---->
<canvas>
<!-- This canvas is overlaid over the previous canvas and is used to
place the rectangle that implements the drag selection box. -->
<rectangle>
x:Name="selectionBox"
Visibility="Collapsed"
Stroke="Black"
StrokeThickness="1"
/>
</canvas>
<!---->


XAML.cs

bool mouseDown = false; // Set to 'true' when mouse is held down.
Point mouseDownPos; // The point where the mouse button was clicked down.

private void Grid_MouseDown(object sender, MouseButtonEventArgs e)
{
// Capture and track the mouse.
mouseDown = true;
mouseDownPos = e.GetPosition(theGrid);
theGrid.CaptureMouse();

// Initial placement of the drag selection box.
Canvas.SetLeft(selectionBox, mouseDownPos.X);
Canvas.SetTop(selectionBox, mouseDownPos.Y);
selectionBox.Width = 0;
selectionBox.Height = 0;

// Make the drag selection box visible.
selectionBox.Visibility = Visibility.Visible;
myCanvas.Children.Contains(selectedElement);
}

private void Grid_MouseUp(object sender, MouseButtonEventArgs e)
{
// Release the mouse capture and stop tracking it.
mouseDown = false;
theGrid.ReleaseMouseCapture();

// Hide the drag selection box.
selectionBox.Visibility = Visibility.Collapsed;

Point mouseUpPos = e.GetPosition(theGrid);


}

private void Grid_MouseMove(object sender, System.Windows.Input.MouseEventArgs e)
{
if (mouseDown)
{

// When the mouse is held down, reposition the drag selection box.

Point mousePos = e.GetPosition(theGrid);

if (mouseDownPos.X < mousePos.X)
{
Canvas.SetLeft(selectionBox, mouseDownPos.X);
selectionBox.Width = mousePos.X - mouseDownPos.X;
}
else
{
Canvas.SetLeft(selectionBox, mousePos.X);
selectionBox.Width = mouseDownPos.X - mousePos.X;
}

if (mouseDownPos.Y < mousePos.Y)
{
Canvas.SetTop(selectionBox, mouseDownPos.Y);
selectionBox.Height = mousePos.Y - mouseDownPos.Y;
}
else
{
Canvas.SetTop(selectionBox, mousePos.Y);
selectionBox.Height = mouseDownPos.Y - mousePos.Y;
}

myCanvas.Children.Contains(selectedElement);

if (selected)
{
selected = false;
if (selectedElement != null)
{
// Remove the adorner from the selected element

//<<i have justifed it after adding the delete button becasue of adorner layer issue>>

aLayer.Remove(aLayer.GetAdorners(selectedElement)[0]);
selectedElement = null;
}
}


if (e.Source != myCanvas)
{
_isDown = true;
_startPoint = e.GetPosition(myCanvas);

selectedElement = e.Source as UIElement;

_originalLeft = Canvas.GetLeft(selectedElement);
_originalTop = Canvas.GetTop(selectedElement);

aLayer = AdornerLayer.GetAdornerLayer(selectedElement);

aLayer.Add(new ResizingAdorner(selectedElement));
selected = true;
e.Handled = true;

}
}
}

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