我正在开发一个应用程序,我有一个问题,我有一个绑定到我的数据库中的表的组合框,当在组合框中选择数据时,我希望自动填充“文本框 1”和“文本框 2”从表中取出数据,这可能吗?例如,当我在组合框中选择“Richard”时,“Richards”、“Address1”和“Postcode”会在文本框中填写。我有一个示例代码可以做到这一点,但它似乎只适用于 Int32,请参见下面的插入。
Public Class Form1
Private Sub cmdGetByIdentifier_Click(sender As Object, e As EventArgs) Handles cmdGetByIdentifier.Click
If Not String.IsNullOrWhiteSpace(txtIdentifier1.Text) Then
Dim Identifier As Int32 = 0
If Int32.TryParse(txtIdentifier1.Text, Identifier) Then
txtCompanyName1.Text = GetCustomerNameByIdentifier(Identifier)
Else
MessageBox.Show("'" & txtIdentifier1.Text & "' is not a valid integer.")
End If
Else
MessageBox.Show("Must enter an identifier to get a company name.")
End If
End Sub
Private Sub cmdGetCustomer_Click(sender As Object, e As EventArgs) Handles cmdGetCustomer.Click
If Not String.IsNullOrWhiteSpace(txtIdentifier2.Text) Then
Dim Identifier As Int32 = 0
If Int32.TryParse(txtIdentifier2.Text, Identifier) Then
Dim Cust As Customer = GetCustomer(Identifier)
txtCompanyName2.Text = Cust.Name
txtContactName2.Text = Cust.ContactName
Else
MessageBox.Show("'" & txtIdentifier1.Text & "' is not a valid integer.")
End If
Else
MessageBox.Show("Must enter an identifier to get a company name.")
End If
End Sub
End Class
Module DatabaseOperations
Public Function GetCustomerNameByIdentifier(ByVal Identifier As Int32) As String
Dim CompanyName As String = ""
Dim Builder As New OleDb.OleDbConnectionStringBuilder With {.Provider = "Microsoft.ACE.OLEDB.12.0", .DataSource = IO.Path.Combine(Application.StartupPath, "Database1.accdb")}
Using cn As New OleDb.OleDbConnection With {.ConnectionString = Builder.ConnectionString}
Using cmd As New OleDb.OleDbCommand With {.Connection = cn}
cmd.CommandText = "SELECT CompanyName FROM Customer WHERE Identifier =@P1"
Dim NameParameter As New OleDb.OleDbParameter With {.DbType = DbType.Int32, .ParameterName = "P1", .Value = Identifier}
cmd.Parameters.Add(NameParameter)
cn.Open()
CompanyName = CStr(cmd.ExecuteScalar)
End Using
End Using
Return CompanyName
End Function
Public Function GetCustomer(ByVal Identifier As Int32) As Customer
Dim Customer As New Customer
Dim CompanyName As String = ""
Dim Builder As New OleDb.OleDbConnectionStringBuilder With {.Provider = "Microsoft.ACE.OLEDB.12.0", .DataSource = IO.Path.Combine(Application.StartupPath, "Database1.accdb")}
Using cn As New OleDb.OleDbConnection With {.ConnectionString = Builder.ConnectionString}
Using cmd As New OleDb.OleDbCommand With {.Connection = cn}
cmd.CommandText = "SELECT Identifier, CompanyName,ContactName FROM Customer WHERE Identifier =@P1"
Dim NameParameter As New OleDb.OleDbParameter With {.DbType = DbType.Int32, .ParameterName = "P1", .Value = Identifier}
cmd.Parameters.Add(NameParameter)
cn.Open()
Dim Reader As OleDb.OleDbDataReader = cmd.ExecuteReader
If Reader.HasRows Then
Reader.Read()
Customer.Identifier = Identifier
Customer.Name = Reader.GetString(1)
Customer.ContactName = Reader.GetString(2)
End If
End Using
End Using
Return Customer
End Function
End Module
Public Class Customer
Public Property Identifier As Int32
Public Property Name As String
Public Property ContactName As String
Public Sub New()
End Sub
End Class