Sometimes you have only the type of an object, which you want to create. Meaning you want to create an object dynamically. This is how you would achieve your goal:

In my case I wanted to create a SPField from its typename.

   1:  string typename = "Microsoft.SharePoint.SPFieldText, Microsoft.SharePoint, "+

   2:      "Version=11.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c";

   3:  Type t = Type.GetType(typename, true, true);

   4:  object newObject = System.Activator.CreateInstance(t, 

   5:      BindingFlags.SetProperty, new object[] { fields, "Title" });

I know one constructor for a SPField is to create a new object with the SPFieldCollection and its name. The problem was that the constructor could be found.

You can view all available constructors with:

   1:  ConstructorInfo[] constructors = t.BaseType.GetConstructors();

After looking back into the SDK, I noticed that SharePoint can be so easy. You can create a SPField like this:

   1:  SPField newField = new SPField(fields, "SPFieldText", "new Field Name");

Next time I will remember :-)

Keywords: Create SPField from typename, Erstellen eines spfield von seinem typ namen