im trying to write a program to calculate BMI for practice. I have it working for the most part but im having trouble with 1 thing. I want to say if its any letter or not a number then display an error message. Here is the code that I need help with. How do I make it work?

ElseIf (ComboBox2.Text) = ???? Then
MsgBox("ERROR2: Please Select Your Height In The Inches Box.")

theres more than that but this is the only part giving me trouble

IsNumeric Function: IsNumeric returns True if the data type of Expression is Boolean, Byte, Decimal, Double, Integer, Long, SByte, Short, Single, UInteger, ULong, or UShort, or an Object that contains one of those numeric types. It also returns True if Expression is a Char or String that can be successfully converted to a number.

IsNumeric returns False if Expression is of data type Date or of data type Object and it does not contain a numeric type. IsNumeric returns False if Expression is a Char or String that cannot be converted to a number.

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