c# GMap

using System;
using System.Collections.Generic;
using
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace gmap1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void gMapControl1_Load(object sender, EventArgs e)
        {
            gmap.MapProvider =
             =
            gmap.SetCurrentPositionByKeywords("Maputo, Mozambique");
        }
    }
}
上面代码提示错误
错误    1    “”不包含“SetCurrentPositionByKeywords”的定义，并且找不到可接受类型为“”的第一个参数的扩展方法“SetCurrentPositionByKeywords”(是否缺少 using 指令或程序集引用?)