vs2019 下用 vb.net编写窗体程序连接 mongodb4.2的方法

Imports MongoDB.Bson

Public Class vbtest
 Public _id As ObjectId
 Public content As String
End Class

Imports MongoDB.Bson
Imports MongoDB.Driver

Public Class vbmongo
 Public client
 Public collection As IMongoCollection(Of vbtest)
 Public database As IMongoDatabase
 Public mlist As List(Of vbtest)
 Public builder As FilterDefinitionBuilder(Of vbtest) = New FilterDefinitionBuilder(Of vbtest)
 Public filter As FilterDefinition(Of vbtest)
 Public Sub New(ByVal dbname As String, ByVal collectionname As String)
  client = New MongoClient("mongodb://127.0.0.1:27017")
  database = client.GetDatabase(dbname)
  collection = database.GetCollection(Of vbtest)(collectionname)
 End Sub

 Public Async Function loadrecords() As Task(Of List(Of vbtest))
  filter = builder.Ne(Of ObjectId)("_id", New ObjectId())//_id不等于空的记录，通过这种方法蹩脚的实现了查找全部的功能Builder的大多数条件设置函数都用到了泛型Ne（Of TField）
  Dim mlist As List(Of vbtest) = Await collection.Find(filter).ToListAsync()//TField可以理解为 type of field 对应的是实体类中字段的数据类型例如 OBjectId或者String等等
  Return mlist
 End Function
 Public Async Function loadone(ByVal _id As String) As Task(Of vbtest)
  filter = builder.Eq(Of ObjectId)("_id", New ObjectId(_id))
  Dim mlist As vbtest = Await collection.Find(filter).FirstOrDefaultAsync()
  Return mlist
 End Function

 Public Async Function updateone(ByVal _id As String, ByVal doc As vbtest) As Task(Of vbtest)
  filter = builder.Eq(Of ObjectId)("_id", New ObjectId(_id))
  Dim up As UpdateDefinitionBuilder(Of vbtest) = New UpdateDefinitionBuilder(Of vbtest)()
  Dim updef As UpdateDefinition(Of vbtest)
  updef = up.Set(Of String)("content", doc.content)
  '.Set(Of String)("content", doc)
  collection.UpdateOneAsync(filter, updef)
 End Function

End Class

Public Class vbmongoT(Of T)
 Public client
 Public collection As IMongoCollection(Of T)
 Public database As IMongoDatabase
 Public mlist As List(Of T)
 Public builder As FilterDefinitionBuilder(Of T) = New FilterDefinitionBuilder(Of T)
 Public up As UpdateDefinitionBuilder(Of T)
 Public updef As UpdateDefinition(Of T)
 Public filter As FilterDefinition(Of T)
 Public Sub New(ByVal dbname As String, ByVal collectionname As String)
  client = New MongoClient("mongodb://127.0.0.1:27017")
  database = client.GetDatabase(dbname)
  collection = database.GetCollection(Of T)(collectionname)
 End Sub

 Public Async Function loadrecords() As Task(Of List(Of T))
  filter = builder.Ne(Of ObjectId)("_id", New ObjectId())
  Dim mlist As List(Of T) = Await collection.Find(filter).ToListAsync()
  Return mlist
 End Function
 Public Async Function loadone(ByVal _id As String) As Task(Of T)
  filter = builder.Eq(Of ObjectId)("_id", New ObjectId(_id))//_id满足查找条件的记录，Builder的大多数条件设置函数都用到了泛型：例如Ne（Of TField）
  Dim mlist As T = Await collection.Find(filter).FirstOrDefaultAsync() 
  Return mlist 
 End Function 
 Public Async Function updateone(ByVal filter As FilterDefinition(Of T), ByVal updef As UpdateDefinition(Of T)) As Task(Of T) 
  'updef = up.Set(Of String)("content", doc.content) '.Set(Of String)("content", doc) 
  Await collection.UpdateOneAsync(filter, updef) 
 End Function 
End Class

Imports MongoDB.Bson
Imports MongoDB.Driver

Public Class Form1
 Public client
 Public bsdoc As vbtest
 Public collection As IMongoCollection(Of vbtest)
 Public database As IMongoDatabase
 Public mlist As List(Of vbtest)
 Public builder As FilterDefinitionBuilder(Of vbtest) = New FilterDefinitionBuilder(Of vbtest)
 Public vm As vbmongoT(Of vbtest) = New vbmongoT(Of vbtest)("meandmycoach", "vbtest")
 Public filter As FilterDefinition(Of vbtest)
 Private Async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
  bsdoc.content = RichTextBox1.Text
  vm.filter = vm.builder.Eq(Of ObjectId)("_id", New ObjectId(ComboBox1.Text))
  vm.up = New UpdateDefinitionBuilder(Of vbtest)
  vm.updef = vm.up.Set(Of String)("content", bsdoc.content)
  'vm.up.Set(Of String)("content", bsdoc.content)
  vm.updef = vm.up.Combine(vm.updef)
  vm.updateone(vm.filter, vm.updef)

 End Sub

 Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
  vm = New vbmongoT(Of vbtest)("meandmycoach", "vbtest")
  Dim bsdoc As vbtest = New vbtest()
 End Sub

 Private Async Sub PictureBox1_Click(sender As Object, e As EventArgs) Handles PictureBox1.Click
  mlist = Await vm.loadrecords()
  For i As Integer = 0 To mlist.Count - 1
   ComboBox1.Items.Add(mlist(i)._id.ToString())
  Next
  ComboBox1.Text = ComboBox1.Items(0)
  Label2.Text = mlist.Count.ToString()
 End Sub

 Private Sub RichTextBox1_TextChanged(sender As Object, e As EventArgs) Handles RichTextBox1.TextChanged

 End Sub

 Private Async Sub ComboBox1_TextChanged(sender As Object, e As EventArgs) Handles ComboBox1.TextChanged
  bsdoc = Await vm.loadone(ComboBox1.Text)
  RichTextBox1.Text = bsdoc.content
 End Sub

 Private Async Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedIndexChanged

 End Sub
End Class