Dynamically Create instance for class

Question

Hi i have 2 class (YarnBLL, DyingBLL) with same property.

 

i need to create a instace based on switch case

public String insave(String name)
{
    var obj;
    switch (name)
    {
        case "YARN":
            obj = new YarnBLL();
            break;
        case "WEAVING":
            obj = new DyingBLL();
            break;
        default:
            break;
    }
  obj.InDate = Utils.ConvertStringToDate(txtDate.Text);
  obj.CategoryName = ddlCategory.SelectedItem.ToString();
  obj.Save();
}

 Here i have an error in

    var obj;

 it shows 

Error 1 Implicitly-typed local variables must be initialized