Question

我正在使用链接到SQL服务器的树视图。我有两个桌子区域和街道，区域有很多街道。我填充了我的树视图，在每个区域只有与该区域相关的街道。我的街道到达第一区域，第二个区域节点是街道加上第一个区域节点的街道，依此类推，我需要消除额外的街道。这是我的代码：

private void PopulateTreeview1()
        {

            DataTable dt = new DataTable();
            DataTable dt2 = new DataTable();
            DataTable dt3 = new DataTable();

            SqlCommand cmd1 = cnn.CreateCommand();
            cmd1.CommandText = "select areaId,areaName from area";
            SqlDataAdapter sdr1 = new SqlDataAdapter(cmd1);
            cmd1.CommandType = CommandType.Text;
            cmd1.Connection = cnn;
            sdr1.Fill(dt);


            for (int i = 0; i < dt.Rows.Count; i++)
            {
                // Current areaId and areaname is stored
                string areaID = dt.Rows[i]["areaId"].ToString();
                string areaName = dt.Rows[i]["areaName"].ToString();

                TreeNode AreaNode = new TreeNode(areaName);


                SqlCommand cmd2 = cnn.CreateCommand();
                cmd2.CommandText = "SELECT streetId, streetName FROM street WHERE areaId = @areaId";
                cmd2.CommandType = CommandType.Text;
                cmd2.Parameters.AddWithValue("@areaId", areaID);
                SqlDataAdapter sdr2 = new SqlDataAdapter(cmd2);
                cmd2.Connection = cnn;
                sdr2.Fill(dt2);

                for (int j = 0; j < dt2.Rows.Count; j++)
                {

                    // Current StreetName and StreetId is stored
                    string streetId = dt2.Rows[j]["streetId"].ToString();
                    string streetName = dt2.Rows[j]["streetName"].ToString();
                    // A TreeNode is created with current StreetName 
                    TreeNode StreetNode = new TreeNode(streetName);
                    // Current StreetNode is added as child node of AreaNode
                    AreaNode.Nodes.Add(StreetNode);
                     }

                treeView1.Nodes.Add(AreaNode);

            }

        }

请我帮忙。

Answer 1

我找到了我的解决方案，我在其间插入了dt2.Clear（），它正常工作

cmd2.Connection = cnn;
                dt2.Clear();
                sdr2.Fill(dt2);

树视图中的子节点重复值c＃

1 个答案: