How do I get the length of a string field?

Question

For a string field, is there a way to get the defined length of the field? For example say I allow a maximum of 10 chars, can I get that in apex?

I am not asking how to get the length of a string (i.e. str.length()).

Answer 1

You are looking for DescribeFieldResult.getLength():

For string fields, returns the maximum size of the field in Unicode characters (not bytes).

Schema.DescribeFieldResult F = Account.AccountNumber.getDescribe();
Integer lengthOfField = F.getLength();

Answer 2

This is pretty straightforward in both Apex and Visualforce using describes:

Apex:

Integer len = SObjectType.Object__c.Fields.Field__c.Length;

Visualforce:

{!$ObjectType.Object__c.Fields.Field__c.Length}

Answer 3

integer fieldLength = Schema.SObjectType.CustObj__c.fields.CustField__c.getLength();

for more info