.NET 2.0 - WinForm Control - DataGridView 数据绑定

在应用开发中常常用到这样的应用： DataGridView用来显示全体数据，还有由一些TextBox控件来提供修改功能。这里如果用挨个赋值的办法就不好了。.NET中提供的一个重要的技术就是——数据绑定。数据绑定中几个重要对象及属性有：Control.DataSource属性，BindingSource对象，Form.BindingContext属性。

这里通过一个例子来说明WinForm开发中如何使用数据绑定。首先有数据结构形如：（这里使用NorthWind的Sample数据。）

Customers和Orders数据是1：n的关系，Orders和OrdersDetails数据是1：n的关系。

因此设计Form如图，ListView绑定Custormers数据，入力控件绑定Customers里数据的其他字段。OrdersDataGridView绑定Orders数据，DetaiDataGridView绑定Order Details数据。

首先通过DataSet的DataRelation建立三表的关系：

PrivateSubQueryData()SubQueryData()

IfobjConnIsNothingThenReturn
objDataSet=NewDataSet("Data")

DimstrSqlAsString="select*fromcustomers"
DimobjDbAdapterAsOleDb.OleDbDataAdapter=NewOleDb.OleDbDataAdapter(strSql,objConn)
objDbAdapter.Fill(objDataSet,"Customers")

objDbAdapter.SelectCommand.CommandText="select*fromorders"
objDbAdapter.Fill(objDataSet,"Orders")

objDbAdapter.SelectCommand.CommandText="select*from[orderdetails]"
objDbAdapter.Fill(objDataSet,"OrderDetails")

objDataSet.Relations.Add("CustomerOrder",objDataSet.Tables("Customers").Columns("CustomerID"),objDataSet.Tables("Orders").Columns("CustomerID"))
objDataSet.Relations.Add("OrderDetail",objDataSet.Tables("Orders").Columns("OrderID"),objDataSet.Tables("OrderDetails").Columns("OrderID"))

EndSub

通过BindingSource绑定到DataGridView上，需要注意的是比较.NET 1.1的绑定，这里用BindingSource取代，在创建DataGridViewOrders的BindingSource对象的DataSource使用的是customBindingSource，而DataMember是Customers表和Orders表的DataRelation的名字——CustomerOrder。

orderBindingSource.DataSource = customBindingSource
orderBindingSource.DataMember = "CustomerOrder"

同理Detail的BindingSource对象的DataSource使用的是orderBindingSource，而DataMember是Orders表和Order Details表的DataRelation的名字——OrderDetail。

detailBindingSource.DataSource = orderBindingSource
detailBindingSource.DataMember = "OrderDetail"

PrivateSubBindData()SubBindData()

IfobjDataSetIsNothingThenReturn

DimcustomBindingSourceAsBindingSource=NewBindingSource
DimorderBindingSourceAsBindingSource=NewBindingSource
DimdetailBindingSourceAsBindingSource=NewBindingSource

customBindingSource.DataSource=objDataSet
customBindingSource.DataMember="Customers"

orderBindingSource.DataSource=customBindingSource
orderBindingSource.DataMember="CustomerOrder"

detailBindingSource.DataSource=orderBindingSource
detailBindingSource.DataMember="OrderDetail"

Me.lstCustom.DataSource=customBindingSource
Me.lstCustom.ValueMember="ContactName"
Me.lstCustom.DisplayMember="ContactName"

Me.DataGridView1.DataSource=orderBindingSource
Me.DataGridView2.DataSource=detailBindingSource
Me.DataGridView1.AutoResizeColumns()
Me.DataGridView2.AutoResizeColumns()

Me.txtName.DataBindings.Add("Text",customBindingSource,"ContactName")
Me.txtContactTitle.DataBindings.Add("Text",customBindingSource,"ContactTitle")
Me.txtAddress.DataBindings.Add("Text",customBindingSource,"Address")
Me.txtCity.DataBindings.Add("Text",customBindingSource,"City")
Me.txtRegion.DataBindings.Add("Text",customBindingSource,"Region")
Me.txtPostalCode.DataBindings.Add("Text",customBindingSource,"PostalCode")
Me.txtPhone.DataBindings.Add("Text",customBindingSource,"Phone")
Me.txtFax.DataBindings.Add("Text",customBindingSource,"Fax")
Me.txtCountry.DataBindings.Add("Text",customBindingSource,"Country")

EndSub

而浏览数据，可以通过BindingManagerBase的Position来控制：

PrivateSubbtnFirst_Click()SubbtnFirst_Click(ByValsenderAsSystem.Object,ByValeAsSystem.EventArgs)HandlesbtnFirst.Click
'DimbindingAsBinding=Me.txtName.DataBindings("Text")
'DimmanagerAsBindingManagerBase=binding.BindingManagerBase
DimmanagerAsBindingManagerBase=Me.BindingContext(Me.lstCustom.DataSource)
manager.Position=0
EndSub

PrivateSubbtnPrev_Click()SubbtnPrev_Click(ByValsenderAsSystem.Object,ByValeAsSystem.EventArgs)HandlesbtnPrev.Click
DimmanagerAsBindingManagerBase=Me.BindingContext(Me.lstCustom.DataSource)
Ifmanager.Position>0Then
manager.Position-=1
EndIf
EndSub

PrivateSubbtnNext_Click()SubbtnNext_Click(ByValsenderAsSystem.Object,ByValeAsSystem.EventArgs)HandlesbtnNext.Click
DimmanagerAsBindingManagerBase=Me.BindingContext(Me.lstCustom.DataSource)
Ifmanager.Position<manager.Count-1Then
manager.Position+=1
EndIf
EndSub

PrivateSubbtnLast_Click()SubbtnLast_Click(ByValsenderAsSystem.Object,ByValeAsSystem.EventArgs)HandlesbtnLast.Click
DimmanagerAsBindingManagerBase=Me.BindingContext(Me.lstCustom.DataSource)
manager.Position=manager.Count-1
EndSub