Can't give multiple conditions to single sign in button

[Anonymous]

I'm creating an app which has to check if the User() is in the database with his email. From that I need to check the role of this person (Trainee, Instructor or Admin).

Based on this the button needs to direct them to the right screen. If their email is not in the database, an error pops up saying they need to register.

My code is currently as follows: 

If(

    Text(TextInput1) in '[dbo].[vStudents]'.Email && LookUp('[dbo].[vEmployees]',Type= "Student",       Navigate(HomeScreen_Trainee,ScreenTransition.None)),

    If(

       Text(TextInput1) in '[dbo].[vTeacherCourses]'.Email && LookUp('[dbo].[vEmployees]',Type= "Teacher",                           Navigate(HomeScreen_Instructor,ScreenTransition.None)),false);

Who knows how to solve this?!

[chrisog · Accepted solution]

Hi @Anonymous,

A few smaller issues before I look at the formula as a whole:

Looking at your existing code, the first thing to mention is the LookUp() function. The syntax for LookUp() is LookUp(DataSource, Condition, Result)

This section:

LookUp('[dbo].[vEmployees]',Type= "Student",

Is missing a Result and needs to be closed with ) before moving on to the If-true statement.

Secondly, there is a function, Switch(), which is great for replacing nested If statements. The syntax is Switch(switch_value,  match_value, match_result, ..., default_value). To explain this in real terms, you may have something like Switch(true, variable1 > 10, "Variable is greater than 10", variable > 5, "Variable is greater than 5", "Variable is not greater than 5")

This is a rather simple example, but it shows how you can set an initial switch value, and then each of the match values compare to that switch value and return the match result if true. Bear in mind, the Switch function always returns the first result that matches. 

Switch is easier to maintain than mulitple Ifs, and you can have as many conditions as you want.

Now assuming I have this correct and the user types their name (or identifying text) into the TextInput1 and then presses a button to submit, I will try to provide 2 examples of solutions. Unfortunately, I do not quite understand the configuration of your data to solve the opened LookUp functions but I will try.

If(

    Text(TextInput1) in '[dbo].[vStudents]'.Email && LookUp('[dbo].[vEmployees]',Text(TextInput1) in Email, Type) = "Student",       Navigate(HomeScreen_Trainee,ScreenTransition.None),

    If(

       Text(TextInput1) in '[dbo].[vTeacherCourses]'.Email && LookUp('[dbo].[vEmployees]',Text(TextInput1) in Email, Type)= "Teacher", Navigate(HomeScreen_Instructor,ScreenTransition.None),Notify("The employee entered is not in the database, NotificationType.Error));

Switch(LookUp('[dbo].[vEmployees]',Text(TextInput1) in Email, Type), "Student",  Navigate(HomeScreen_Trainee, ScreenTransition.None),Notify("This student is not found in the database", NotificationType.Error)) , "Teacher", If(TextInput1.Text in '[dbo].[vTeacherCourses]'.Email,Navigate(HomeScreen_Instructor,ScreenTransition.None),Notify("The teacher entered is not in the database", NotificationType.Error)))

I hope this makes sense. Feel free to message me you need more help or ask to clarify anything within my post.

[Anonymous]

Hi @chrisog ,

Thank you for your fast reply. 

I've tried both solutions and can't seem to make it work. It says it misses the End of Fomula where the ";" is at the first solution. And the second one stops at the vStudent and does not look at the teacher.

The vEmployees database is as follows:

|Name|Email|Type|

|............|...........|Student|

|............|...........|Instructor|

|............|...........|Admin|

|............|...........|Student|

The other are a subset of this.

The real challange is to be able to link the email to the Type and then make the Type determine the behavior of the button.

Attached is a Screenshot of the loginscreen. 

[Anonymous · Accepted solution]

@Anonymous you should be able to remove the second "If(" code snippet and @chrisog 1st solution will work (see pic), or add another ")" before the ";" .

Nested Ifs are difficult to write and maintain but the If function can handle a number of If/Else conditions (up to 10 I think?) inside the same If() command like this:

If( if-this1, then-that1,   if-this2, then-that2,  if-this3, then-that3 ... , else-this ) link

Once I found PowerApps could handle this functionality I use it all the time. Very easy to maintain and write, if you ask me.

[Anonymous]

Good morning @Anonymous ,

Removing the first "If(" did the trick!

Thank you @chrisog for taking the time to help out a starting PowerApps Developer!