将表值添加到树视图？ [英] Adding table values to a treeview?

问题描述

我使用的是Vb 2008快递版，对于树视图来说我是一个新手。我对如何连接数据库有基本的了解。我正在使用的数据库是一个微软访问数据库，并有大量的表与各种信息。我需要将其中两个表放入树视图中。一个有2列称为日期和日期ID，日期将是树视图上的主要节点。另一个表有8个列，其中包括第一个表中的相应日期ID，采购订单ID和采购订单号。子节点将是采购订单编号。



现在我知道通过微软访问数据库在树视图上有一堆教程，但我没有找到具体的根据我的需要，他们只是将数据库中的所有数据转储到表中。我只想要两个表的具体内容。如果有人可以帮我解决这个问题，我将非常感激。如果需要我可以提供更多信息我正在使用什么或其他什么。！



这里是我现在的代码，有两个我一直在尝试的变种两者都包括在内

  Imports  System.Data 
 < span class =code-keyword> Imports  System.Data.OleDb 
  Imports  System.Data.SqlClient 
 
 公开 类 Form1 
  Dim  mypath =   I：\ Casegoods \Database\Expertpetrolia.mdb 
  Dim  conn 作为 新 OleDbConnection（  Provider = microsoft.ace.oledb.12.0; Data Source =& mypath）
 < span class =code-ke yword> Dim  cmd 作为 OleDbCommand 
  Dim  dr  As  OleDbDataReader 
  Dim  sql1 =   SELECT * FROM Supply_Date ORDER BY [Due_Date] 
  Dim  sql2 =   SELECT * FROM Supply_Date INNER JOIN Total_Purchase ON Supply_Date.Date_Id = Total_Purchase.Date_Id ORDER BY [Due_Date] 
 
  Dim  dr2  As  OleDbDataReader 
 
  '  Dim sql2 =SELECT * FROM Total_Purchase ORDER BY [Date_Id] 
  Dim  cmd2 作为 OleDbCommand 
 
 
 
 
 
 
 私有  Sub  Form1_Load（ ByVal  sender 作为系统。对象， ByVal  e  As  System.EventArgs）句柄  MyBase  .Load 
 
 
  Dim  cmd 作为 OleDbCommand 
 使用 conn 
 
 
 
 cmd = 新 OleDbCommand（sql1，conn）
 cmd2 = 新 OleDbCommand（sql2，conn）
 conn.Open（）
 
 dr = cmd.ExecuteReader 
 dr2 = cmd2.ExecuteReader 
 
 如果 dr.HasRows 那么 
     dr.Read（）
  Dim  parent  As   String  =（dr.Item（  Due_Date））
 
 如果 DateDiff（Microsoft .VisualBasic.DateInterval.Day，今天，（dr.Item（  Due_Date）））> -10 然后 
 TreeView1.Nodes.Add（父）
 如果（dr2 .Item（  Date_Id））=（dr.Item（  Date_Id））然后 
 TreeView1.Nodes（parent） .Nodes.Add（dr2.Item（  Purchase_Order_Number））
 
 结束 如果 
 
 结束 如果 
 
 
 循环 
 < span class =code-keyword> Else  
 MsgBox（ 找不到任何东西）
 结束 如果 
 
 
 
 dr.Close（）
 
 结束 使用 
 
 结束  Sub  
 '  Private Sub Form1_Load（ByVal sender As System.Object，ByVal e As System.EventArgs）Handles MyBase.Load  
 
 
 '  Dim cmd As OleDbCommand  
 ' 使用conn  
 
 
 
 '  cmd =新OleDbCommand（sql1，conn） 
 ' 'cmd2 =新的OleDbCommand（sql2，conn） 
 '  conn.Open（） 
 
 
 '  Dim dr As OleDbDataReader = cmd.ExecuteReader  
 ' 'Dim dr2 As OleDbDataReader = cmd2.ExecuteReader  
 
 '  do dr dr.Read（） 
 '  Dim str1 As String = dr.Item（Due_Date） 
 '  Dim str2 As String = dr。项目（Date_Id） 
 ' 尝试 
 '  Dim str3 As String = dr.Item（date_id） 
 '  Dim str4 As String = dr.Item（Purchase_Order_Number） 
 ' 如果DateDiff（Microsoft.VisualBasic.DateInterval.Day，Today，（dr.Item（Due_Date）））> -10然后 
 '  TreeView1.Nodes.Add（str1） 
 ' 如果str2 = str3那么 
  '  TreeView1.Nodes（0）.Nodes.Add（New TreeNode（str4）） 
  ' 结束如果 
 ' 结束如果 
 '  Catch ex As Exception  
 '  MsgBox（ex.Message，MsgBoxStyle.Critical，stumbid dims） 
 ' 结束尝试 
 
 
 ' 循环 
 
 ' 结束使用 
 
 ' 结束子 
 结束 类 

解决方案

看看这里：使用HierarchyID加载TreeView [ ^ ]。

sql server数据库有一个示例算法实现，但主要思路是一样的。您需要根据需要进行更改。

您必须使用此代码进行一些操作才能使其正常工作。

数据库连接和数据选择：

  Dim 连接 As  新 Data.OleDb.OleDbConnection（  Provider = Microsoft.Jet.OLEDB.4.0; Data Source = YourDatabseName.mdb;）
  Dim 命令作为 新 Data.OleDb.OleDbCommand（  SELECT * FROM TableName，Connection）
 
 Connection.Open（）
  Dim  Reader  As  OleDbDataReader = Command.ExecuteReader 
 
   < span class =code-keyword> while  Reader.Read（）
  Dim  str1  As   String  = Reader.Item（  Column1Name）
  Dim  str2  As   String  = Reader.Item（  Column2Name）
  Dim  str3  As   String  = Reader.Item（  Column3Name）
 循环 
 
 Connection.Close（）

至于更新树视图：

 TreeView1.Nodes.Add（新 TreeNode（  NewNode））
 TreeView1.Nodes（ 0 ）。Nodes.Add（新 TreeNode（  ChildNode））
 TreeView1.Nodes（ 0 ）。Nodes.Add（< span class =code-keyword>新 TreeNode（  ChildNode））
 TreeView1.Nodes（ 0 ）。节点（ 0 ）。Nodes.Add（新 TreeNode（  ChildChildNode））

I am using Vb 2008 express edition and am very new to treeviews. i have basic knowledge of how to connect to a database. the database i am working with is a microsoft access database and has a large amount of tables with various information. two of these tables i need to put into a treeview. one has 2 columns called date and date id, the date will be the main nodes on the treeview. the other table has 8 colums, among them are the corresponding date id's from the first table, the purchase order id and the purchase order number. the child nodes will be the purchase order number.

Now i know there are a bunch of tutorials out there on treeview population through microsoft access databases but i have found none specifically with what i need, they are all just about dumping ALL the data from the database into the table. i just want specific contents of two tables. if someone could help me out with this i would be very grateful. i can give more information if needed on what i am working with or anything else.!

here is my code as of now, there are two variants i have been trying both are included

Imports System.Data
Imports System.Data.OleDb
Imports System.Data.SqlClient

Public Class Form1
    Dim mypath = "I:\Casegoods\Database\Expertpetrolia.mdb"
    Dim conn As New OleDbConnection("Provider = microsoft.ace.oledb.12.0;Data Source=" & mypath)
    Dim cmd As OleDbCommand
    Dim dr As OleDbDataReader
    Dim sql1 = "SELECT * FROM Supply_Date ORDER BY [Due_Date]"
    Dim sql2 = "SELECT * FROM Supply_Date INNER JOIN Total_Purchase ON Supply_Date.Date_Id = Total_Purchase.Date_Id ORDER BY [Due_Date]"

    Dim dr2 As OleDbDataReader

    'Dim sql2 = "SELECT * FROM Total_Purchase ORDER BY [Date_Id]"
    Dim cmd2 As OleDbCommand






    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load


        Dim cmd As OleDbCommand
        Using conn



            cmd = New OleDbCommand(sql1, conn)
            cmd2 = New OleDbCommand(sql2, conn)
            conn.Open()

            dr = cmd.ExecuteReader
            dr2 = cmd2.ExecuteReader

            If dr.HasRows Then
                Do While dr.Read()
                    Dim parent As String = (dr.Item("Due_Date"))

                    If DateDiff(Microsoft.VisualBasic.DateInterval.Day, Today, (dr.Item("Due_Date"))) > -10 Then
                        TreeView1.Nodes.Add(parent)
                        If (dr2.Item("Date_Id")) = (dr.Item("Date_Id")) Then
                            TreeView1.Nodes(parent).Nodes.Add(dr2.Item("Purchase_Order_Number"))

                        End If

                    End If


                Loop
            Else
                MsgBox("No Things found")
            End If



            dr.Close()

        End Using

    End Sub
    'Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load


    '    Dim cmd As OleDbCommand
    '    Using conn



    '        cmd = New OleDbCommand(sql1, conn)
    '        'cmd2 = New OleDbCommand(sql2, conn)
    '        conn.Open()


    '        Dim dr As OleDbDataReader = cmd.ExecuteReader
    '        ' Dim dr2 As OleDbDataReader = cmd2.ExecuteReader

    '        Do While dr.Read()
    '            Dim str1 As String = dr.Item("Due_Date")
    '            Dim str2 As String = dr.Item("Date_Id")
    '            Try
    '                Dim str3 As String = dr.Item("date_id")
    '                Dim str4 As String = dr.Item("Purchase_Order_Number")
    '                If DateDiff(Microsoft.VisualBasic.DateInterval.Day, Today, (dr.Item("Due_Date"))) > -10 Then
    '                    TreeView1.Nodes.Add(str1)
    '                    If str2 = str3 Then
    '                        TreeView1.Nodes(0).Nodes.Add(New TreeNode(str4))
    '                    End If
    '                End If
    '            Catch ex As Exception
    '                MsgBox(ex.Message, MsgBoxStyle.Critical, "stupid dims")
    '            End Try


    '        Loop

    '    End Using

    'End Sub
End Class

解决方案

Have a look here: Loading a TreeView using HierarchyID[^].
There is a sample algorithm implementation for sql server database, but the main idea is the same. You need to change it to your needs.

You'll have to play around a bit with this code to get it working for you.
Database connection and data selection:

Dim Connection As New Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=YourDatabseName.mdb;")
Dim Command As New Data.OleDb.OleDbCommand("SELECT * FROM TableName", Connection)

Connection.Open()
Dim Reader As OleDbDataReader = Command.ExecuteReader

Do While Reader.Read()
    Dim str1 As String = Reader.Item("Column1Name")
    Dim str2 As String = Reader.Item("Column2Name")
    Dim str3 As String = Reader.Item("Column3Name")
Loop

Connection.Close()

As for updating the treeview:

TreeView1.Nodes.Add(New TreeNode("NewNode"))
TreeView1.Nodes(0).Nodes.Add(New TreeNode("ChildNode"))
TreeView1.Nodes(0).Nodes.Add(New TreeNode("ChildNode"))
TreeView1.Nodes(0).Nodes(0).Nodes.Add(New TreeNode("ChildChildNode"))

这篇关于将表值添加到树视图？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！