PowerApps Input Validation

Overview:  Validation can be handled in a multitude of ways in Power Apps, this technique I used for a fairly advanced set of Validation Requirements.

Basic Validation Example
To check that at least 1 of these two textInput box has been filled in.  Add this function to the DisplayMode:
If((IsBlank(srchMemberAccNo.Text)) && (IsBlank(srchMemberEmail.Text)), DisplayMode.Disabled, DisplayMode.Edit)

There are a number of ways to check if data exists in a control, I just try keep them consistent throughout my logic.  Here is a good approach: If(Not(IsBlank(txtBox1.Text)),<true>,<false>)