如何在Tkinter Treeview中实现选中行滚动至可视区域？

要复现PyQt中scrollToItem（将选中行滚动到可视区域居中）的行为，你需要调整moveDown方法的逻辑，同时跟踪当前选中行的索引，确保每次点击按钮时正确切换到下一行并滚动到可视区域。以下是修改后的完整代码：

import tkinter as tk
import tkinter.ttk as ttk

class App:
    def moveDown(self):
        children = self.tree.get_children()
        max_index = len(children) - 1
        # 到达最后一行时停止
        if self.current_row >= max_index:
            return
        
        self.current_row += 1
        target_item = children[self.current_row]
        # 选中目标行
        self.tree.selection_set(target_item)
        # 滚动到该行使其可见
        self.tree.see(target_item)
        
        # 额外实现居中效果（可选）
        self.center_row(target_item)

    def center_row(self, item):
        # 获取Treeview的可见区域信息
        yview = self.tree.yview()
        # 获取总行数和行高比例
        total_rows = len(self.tree.get_children())
        # 计算目标行的居中位置比例
        target_pos = (self.current_row + 0.5) / total_rows
        # 调整滚动位置使目标行居中
        self.tree.yview_moveto(target_pos - (yview[1] - yview[0])/2)

    def __init__(self, master):
        self.frame = ttk.Frame(master)
        self.frame.pack(fill=tk.BOTH, expand=True)
        cols = (('Col1', 20), ('Col2', 20))
        self.tree = ttk.Treeview(self.frame, columns=[x[0] for x in cols], show='headings', height=5)
        for col, wdth in cols:
            self.tree.heading(col, text=col)
            self.tree.column(col, width=wdth)
        clist = [('A','1'),('B','2'),('C','3'),('D','4'),('E','5'),('F','6'),('G','7'),('H','8'),('I','9'),('J','10'),('K','11'),('L','12'),]
        for item in clist:
            self.tree.insert('', tk.END, values=item)
        
        # 初始化当前行索引并选中第一行
        self.current_row = 0
        children = self.tree.get_children()
        if children:
            self.tree.selection_set(children[self.current_row])
        
        self.tree.grid(row=0, column=0, rowspan=5, columnspan=1, sticky='nsew')
        self.fwdbutton = ttk.Button(self.frame, text='>', command=self.moveDown)
        self.fwdbutton.grid(row=30, column=20, rowspan=1, columnspan=1, sticky='nsew')

root = tk.Tk()
app = App(root)
root.mainloop()

关键说明： #

• 跟踪当前行索引：通过self.current_row记录当前选中行的位置，避免依赖selection()的不确定性。
• 选中并滚动：使用selection_set选中目标行，再调用see()确保该行进入可视区域。
• 居中效果优化：额外实现的center_row方法通过计算滚动比例，让目标行居中显示，更贴近PyQt中PositionAtCenter的效果。

内容的提问来源于stack exchange，提问作者John