綁定（「<Button-2>」，..）不tk.canvas

Question

我使用MonsterBat分身所示的代碼工作中Move and zoom a tkinter canvas with mouse

它的偉大工程！但是，當我添加一個self.canvas.bind（「<Button-2>」，self.find_nearest）時，完全忽略右鍵單擊。

這裏是修改代碼：

#!/usr/bin/python2.7 
""" 
https://stackoverflow.com/questions/25787523/move-and-zoom-a-tkinter-canvas-with-mouse 
by MonsterBat Doppelganger 
""" 
import Tkinter as tk 
import random 

class Example(tk.Frame): 
def __init__(self, root): 
    tk.Frame.__init__(self, root) 
    self.canvas = tk.Canvas(self, width=400, height=400, background="bisque") 
    self.xsb = tk.Scrollbar(self, orient="horizontal", command=self.canvas.xview) 
    self.ysb = tk.Scrollbar(self, orient="vertical", command=self.canvas.yview) 
    self.canvas.configure(yscrollcommand=self.ysb.set, xscrollcommand=self.xsb.set) 
    self.canvas.configure(scrollregion=(0,0,1000,1000)) 

    self.xsb.grid(row=1, column=0, sticky="ew") 
    self.ysb.grid(row=0, column=1, sticky="ns") 
    self.canvas.grid(row=0, column=0, sticky="nsew") 
    self.grid_rowconfigure(0, weight=1) 
    self.grid_columnconfigure(0, weight=1) 

    #Plot some rectangles 
    for n in range(50): 
     x0 = random.randint(0, 900) 
     y0 = random.randint(50, 900) 
     x1 = x0 + random.randint(50, 100) 
     y1 = y0 + random.randint(50,100) 
     color = ("red", "orange", "yellow", "green", "blue")[random.randint(0,4)] 
     self.canvas.create_rectangle(x0,y0,x1,y1, outline="black", fill=color, activefill="black", tags=n) 
    self.canvas.create_text(50,10, anchor="nw", text="Click and drag to move the canvas\nScroll to zoom.") 

    # This is what enables using the mouse: 
    self.canvas.bind("<ButtonPress-1>", self.move_start) 
    self.canvas.bind("<B1-Motion>", self.move_move) 
    #linux scroll 
    self.canvas.bind("<Button-4>", self.zoomerP) 
    self.canvas.bind("<Button-5>", self.zoomerM) 
    #windows scroll 
    self.canvas.bind("<MouseWheel>",self.zoomer) 
    """ My add """ 
    # find my position 
    self.canvas.bind("<Button-2>", self.find_nearest) 

#move 
def move_start(self, event): 
    self.canvas.scan_mark(event.x, event.y) 
def move_move(self, event): 
    self.canvas.scan_dragto(event.x, event.y, gain=1) 

#windows zoom 
def zoomer(self,event): 
    if (event.delta > 0): 
     self.canvas.scale("all", event.x, event.y, 1.1, 1.1) 
    elif (event.delta < 0): 
     self.canvas.scale("all", event.x, event.y, 0.9, 0.9) 
    self.canvas.configure(scrollregion = self.canvas.bbox("all")) 

#linux zoom 
def zoomerP(self,event): 
    self.canvas.scale("all", event.x, event.y, 1.1, 1.1) 
    self.canvas.configure(scrollregion = self.canvas.bbox("all")) 
def zoomerM(self,event): 
    self.canvas.scale("all", event.x, event.y, 0.9, 0.9) 
    self.canvas.configure(scrollregion = self.canvas.bbox("all")) 

""" The rest of the story """ 
def find_nearest(self,event): 
    print 'nearest to %d,%d' % (event.x, event.y) 
    closest = self.canvas.find_closest(event.x,event.y) 
    if len(closest) == 0: 
     print 'Nothing near' 
    else: 
     print 'Id %s' % closest 

if __name__ == "__main__": 
root = tk.Tk() 
Example(root).pack(fill="both", expand=True) 
root.mainloop() 

我還沒有得到在find_nearest打印。一切都按原樣運行。畫布捲動和縮放。沒有例外。

Answer 1

...當我加... <Button-2> ...，右鍵單擊被完全忽略。

好像Button-2是中間鼠標按鈕（即壓下滾輪）。對於右側的鼠標按鈕，您必須使用Button-3。你行更改爲這一點，它應該工作：

# find my position 
    self.canvas.bind("<Button-3>", self.find_nearest) 

參考見e.g. here：

通常設置在左側和按鈕3右側按鈕1，但左撇子能交換這些職位。