私はアプリケーションに取り組んでおり、質問があります。データベース内のテーブルにバインドされたコンボ ボックスがあります。コンボ ボックスでデータが選択されたときに、'textbox 1' と 'textbox2' が自動的に入力されるようにしたいと考えています。テーブルからのデータで、これは可能ですか? たとえば、コンボ ボックスで「Richard」を選択すると、「Richards」「Address1」と「Postcode」がテキスト ボックスに入力されます。これを行うサンプル コードがありますが、Int32 でしか動作しないようです。以下の挿入を参照してください。
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