程序代码：

public static string GetNearestPoint(AxMap axMap, string LayerName, double x, double y)
        {
            try
            {
                Features features;
                float radius = 100f;
                int num2 = 0;
                do
                {
                    features = SearchLayerFeature(axMap, x, y, LayerName, radius);
                    radius *= 2f;
                    num2++;
                }
                while ((features.Count <= 0) && (num2 < 5));
                string keyValue = "";
                double num3 = 0.0;
                for (int i = 1; i < (features.Count + 1); i++)
                {
                    double num5 = axMap.Distance(x, y, features.Item(i).CenterX, features.Item(i).CenterY);
                    if ((i == 1) || (num5 < num3))
                    {
                        features.Item(1).Layer.KeyField = "Address";／／在执行这句的时候，就会出现异常，这里是什么问题呢？？？？？？？？
                        keyValue = features.Item(i).KeyValue;
                        features.Item(i).Layer.KeyField = "Name";
                        keyValue = keyValue + features.Item(i).KeyValue;
                        num3 = num5;
                    }
                }
                if (!"".Equals(keyValue))
                {
                    keyValue = keyValue + Math.Round(num3, 0).ToString() + "米," + Math.Round(num3, 0).ToString();
                }
                return keyValue;
            }
            catch
            {
                return string.Empty;
            }
        }