RLAlterFrm RLalter = new RLAlterFrm();
RLalter.ShowDialog();

string AlterID = RLalter.textBox1.Text;
string AlterRP = RLalter.textBox2.Text;
string AlterC = RLalter.textBox3.Text;

axMapControl1.ClearLayers();
axMapControl1.Refresh();

try
{
    string strFileName = Application.StartupPath + @"\数据\Roadlamp.mxd";
    //在数据视图中加载地图，供查询操作
    if (axMapControl1.CheckMxFile(strFileName))
    {
        axMapControl1.LoadMxFile(strFileName);
    }
    else
    {
        MessageBox.Show("错误的数据路径：" + strFileName);
    }
}
catch (Exception ex)
{
    MessageBox.Show("Error01 in MainForm.cs" + ex.Message);
}
axMapControl1.Refresh();

string strQK = RLalter.getQueryKey();//获取查询值

//找到图层
IFeatureLayer pfeaturelayer = new FeatureLayer();
pfeaturelayer = axMapControl1.get_Layer(0) as IFeatureLayer;

//找到要素
IQueryFilter pQueryFilter = new QueryFilter();
pQueryFilter.WhereClause = "[RL_ID] = ‘" + strQK + "‘";

IFeatureCursor pFeatureCur = pfeaturelayer.Search(pQueryFilter, false);

IFeature pFeature = null;

pFeature = pFeatureCur.NextFeature();

if (null == pFeature)
{
    MessageBox.Show("对不起！该元素不存在");
}

else
{
    IFields pFields = pFeature.Fields;
IFeatureClass pFeatureClass = pfeaturelayer.FeatureClass;

    //修改属性值 
    int field1 = pFields.FindField("RL_ID");
    int field2 = pFields.FindField("RL_RP");
    int field3 = pFields.FindField("RL_C");
    pFeature.set_Value(field1, AlterID);
    pFeature.set_Value(field2, AlterRP);
    pFeature.set_Value(field3, AlterC);
    pFeature.Store();
    MessageBox.Show("修改成功！","提示");
}
}