Call GetConstructor to get the constructor : ConstructorInfo : Reflection C# Source Code

    
 
using System;
using System.Text;
using System.Reflection;

class MainClass
{
    public static StringBuilder CreateStringBuilder()
    {
        Type type = typeof(StringBuilder);

        Type[] argTypes = new Type[] { typeof(System.String), typeof(System.Int32) };

        ConstructorInfo cInfo = type.GetConstructor(argTypes);

        object[] argVals = new object[] { "Some string", 30 };
        StringBuilder sb = (StringBuilder)cInfo.Invoke(argVals);

        return sb;
    }
}