WPF produces non-repeating random numbers

WPF produces non-repeating random numbers

Generates a given number of random numbers (less than 10) in a given interval range (e.g. [50,99]), requiring no repetition of the resulting random number
First given a variable
min=50;
max=99+1;//habits are caused by different coding rules
n=10;
Okay, on the code.
1.xaml interface Format

<Grid> <textblock x:name= "Tb_screen" horizontalalignment= "left" margin= "59,24,0,0" textwrapping= "Wrap" Tex t= "verticalalignment=" Top "/> <button x:name=" tb_create "content=" button "horizontalalignment=" left "Margin= "144,259,0,0" verticalalignment= "Top" width= "click=" Tb_create_click "/> <textbox x:name=" Txt_min "Horizont Alalignment= "left" height= "margin=" 80,92,0,0 "textwrapping=" Wrap "text=" "verticalalignment=" Top "width=" 70 " rendertransformorigin= "0.462,2.179"/> <textbox x:name= "Txt_max" horizontalalignment= "left" Height= "Margin" = "257,92,0,0" textwrapping= "Wrap" text= "verticalalignment=" Top "width=" "rendertransformorigin="/ > <textblock horizontalalignment= "left" margin= "10,95,0,0" textwrapping= "Wrap" text= "min=" verticalalignment= "Top"/> <textblock horizontalalignment= "left" margin= "186,95,0,0" textwrapping= "Wrap" text= "max=" VerticalAli gnment= "Top"/> <textbox x:Name= "Txt_n" horizontalalignment= "left" height= "" margin= "121,149,0,0" textwrapping= "Wrap" text= "10" Verticalalignment= "Top" width= "/>" <textblock horizontalalignment= "left" margin= "31,152,0,0" TextWrapping= "Wrap" text= "number" verticalalignment= "Top"/></grid>

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WPF produces non-repeating random numbers