How in WPF to make the dialed digits from the buttons displayed in the result row?

If you want a calculator as a standard Windows application. That is, you want to make it so that when you press the buttons with digits appear in the result string. How is this done?
April 7th 20 at 15:31
1 answer
April 7th 20 at 15:33
See, here you will find the solution)

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