how to check if a letter is capital in c# code example

Example 1: c# check if string is only letters and numbers

if (textVar.All(c => Char.IsLetterOrDigit(c))) {
    // String contains only letters & numbers
}

Example 2: if char is upper csharp

char ch1 = 'G'; 
bool result = Char.IsUpper(ch1);

Example 3: how to check if a string contains a capital letter c#

using System.Linq;
str.Any(char.IsUpper);