Only a variety of expressions of the input numbers are allowed ....

In the program, we often use only places that only need to enter numbers. "4", "5", "6", "7", "8", "9"} 'Defines an array DIM ISTG_CHECK_CHAR AS STRING ISTG_CHECK_CHAR = Text1.Text.trim (me.istg_char) if ISTG_CHECK_CHAR = " "Then MessageBox.show (" Type ") Else MessageBox.show (" String ") Endiff (C # Part) Char [] Number = New Char (10) {'0', '1', '2 ',' 3 ',' 4 ',' 5 ',' 9 ',' 7 ',' 8 ',' 9 '}; strng CHECK = TEXTBOX1.TEXT.TRIM (Number); if (Check = = " ) {Messagebox.show ("for digital");} else {messagebox.show ("string");}