我在 linux/UNIX 机器上使用 MonoDevelop IDE,并在 C# 和 .NET 框架中进行编码。我似乎无法弄清楚如何在项目构建时让 Gtk::DrawingArea 显示在父 Gtk.Window 中?
我尝试将 ::drawingArea 对象手动添加到代码中,将其直接放在窗口上(在设计视图中,请参见屏幕截图),然后我还尝试将 ::drawingArea 对象放在固定框中。
下面是我试图实现的代码。设计尽可能基本,所以我可以理解捕获和处理绘图区域的信号 - 它具有父窗口(MainWindow)和绘图区域(drawingarea1)。
我的问题:我怎样才能让一个 drawingArea 对象显示在 Gtk.Window 中?而且,更重要的是,我是否缺少一些东西来使对象响应设置到绘图区域的信号?我希望最终能够在绘图区域窗口内绘图和着色,但到目前为止,我什至无法让绘图区域小部件显示和捕获信号。
提前致谢!
MainWidow.cs
using System;
using Gtk;
public partial class MainWindow : Gtk.Window
{
public DrawingArea d;
public MainWindow() : base(Gtk.WindowType.Toplevel)
{
d = drawingarea1;
Build();
}
protected void OnDeleteEvent(object sender, DeleteEventArgs a)
{
Application.Quit();
a.RetVal = true;
}
protected void OnExpose(object o, ExposeEventArgs args)
{
Console.WriteLine("OnExpose...");
}
protected void OnRealization(object sender, EventArgs e)
{
Console.WriteLine("OnRealization...");
}
protected void OnDragMotion(object o, DragMotionArgs args)
{
Console.WriteLine("OnDragMotion...");
}
}
驱动程序.cs
using System;
using Gtk;
class MainClass
{
public static void Main(string[] args)
{
Application.Init();
MainWindow win = new MainWindow();
// throws NULLREFERENCE EXECPTION
win.d.Show();
win.Show();
Application.Run();
}
}
//********** 部分解决方案 **********//
ColorSelectorDraw.cs
using System;
using Gtk;
using Gdk;
namespace GUIDraw4
{
public class DemoColorSelection : Gtk.Window
{
private Gdk.Color color;
private Gtk.DrawingArea drawingArea;
public DemoColorSelection() : base("Color Selection")
{
BorderWidth = 8;
VBox vbox = new VBox(false, 8);
vbox.BorderWidth = 8;
Add(vbox);
// Create the color swatch area
Frame frame = new Frame();
frame.ShadowType = ShadowType.In;
vbox.PackStart(frame, true, true, 0);
drawingArea = new DrawingArea();
drawingArea.ExposeEvent += new ExposeEventHandler(ExposeEventCallback);
// set a minimum size
drawingArea.SetSizeRequest(400, 250);
// set the color
color = new Gdk.Color(255, 255, 255);
drawingArea.ModifyBg(StateType.Normal, color);
frame.Add(drawingArea);
Alignment alignment = new Alignment(1.0f, 0.5f, 0.0f, 0.0f);
Button button = new Button("_Change the above color");
button.Clicked += new EventHandler(ChangeColorCallback);
alignment.Add(button);
vbox.PackStart(alignment);
ShowAll();
}
protected override bool OnDeleteEvent(Gdk.Event evt)
{
Destroy();
return true;
}
// Expose callback for the drawing area
private void ExposeEventCallback(object o, ExposeEventArgs args)
{
EventExpose eventExpose = args.Event;
Gdk.Window window = eventExpose.Window;
Rectangle area = eventExpose.Area;
window.DrawRectangle(drawingArea.Style.BackgroundGC(StateType.Normal),
true,
area.X, area.Y,
area.Width, area.Height);
args.RetVal = true;
}
private void ChangeColorCallback(object o, EventArgs args)
{
using (ColorSelectionDialog colorSelectionDialog = new ColorSelectionDialog("Changing color"))
{
colorSelectionDialog.TransientFor = this;
colorSelectionDialog.ColorSelection.PreviousColor = color;
colorSelectionDialog.ColorSelection.CurrentColor = color;
colorSelectionDialog.ColorSelection.HasPalette = true;
if (colorSelectionDialog.Run() == (int)ResponseType.Ok)
{
Gdk.Color selected = colorSelectionDialog.ColorSelection.CurrentColor;
drawingArea.ModifyBg(StateType.Normal, selected);
}
colorSelectionDialog.Hide();
}
}
}
}
程序.cs
using System;
using Gtk;
namespace GUIDraw4
{
class MainClass
{
public static void Main(string[] args)
{
Application.Init();
//MainWindow win = new MainWindow();
//win.Show();
DemoColorSelection cs = new DemoColorSelection();
Application.Run();
}
}
}
这似乎至少在 GUI 上建立了一个交互式绘图板。取自csharp.hotexamples.com