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我正在使用鏈接到SQL服務器的樹視圖。我有兩個表區和街道,哪個地區有很多街道。我在每個區域填充我的treeview只有與該地區相關的街道。我要把街道弄到第一區,第二區節點有街道和第一區節點的街道等,我需要消除額外的街道。 這裏是我的代碼:在樹視圖中的子節點中的重複值c#
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);
}
}
請我需要幫助。
正如我認爲,你可以使用JOIN一個SQL查詢'選擇areaID表示,AREANAME,streetName,streetId從area join street on area.areaId == street.areaId'然後根據查詢結果填充網格。 – Valentin
抱歉,但你能解釋更多我應該在哪裏使用這個查詢新手到C# –
我需要解決它與我的例子,因爲我需要添加更多的孩子節點與相同的狀態,請任何人幫助! –