vb.net 数据 GridView 刷新

Question

我在更新 VS 2012 中 VB.net Windows 窗体中的表格时遇到一些问题

我已经从服务数据库设置了数据库，它只需要在本地存储少量数据

当我创建一个新用户时，我正在尝试做什么，它会更新数据 GridView

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    BDate1.Format = DateTimePickerFormat.Custom
    BDate1.CustomFormat = "MM/dd/yyyy"

    If fname.Text <> "" And lname.Text <> "" Then
        If Not cn.State = ConnectionState.Open Then
            cn.Open()
        End If
        ' cn1.Open()
        If rb1.Checked Then
            gen = rb1.Text.ToString
        ElseIf rb2.Checked Then
            gen = rb2.Text.ToString
        End If

        cmd.CommandText = "INSERT INTO StudentTB (FirstName,LastName,Birthday,Avatar,Gender,Grade) values('" & fname.Text & "', '" & lname.Text & "', '" & BDate1.Text & "', '" & AvtarNM.Text & "', '" & gen & "', '" & TxtGrade.Text & "')"
        Dim dt As New DataTable
        dt.Load(cmd.ExecuteReader())
        DataGridView1.DataSource = dt
        ' cmd.ExecuteNonQuery()
        cn.Close()
        fname.Text = ""
        lname.Text = ""

问题是我可以清除表格并使用按钮重新加载它但是它不显示更新的值而不关闭应用程序然后重新打开它，我已经尝试了一些事情但似乎没有什么可以刷新连接和/或更新数据库。任何帮助都会有所帮助。

谢谢

Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click

    'DataGridView1.DataSource = Nothing
     Database1DataSet1.StudentTB.Clear()
    ' Database1DataSet1.refresh()
    ' Dim myda As String
    '  cmd.Dispose()
    ' cmd.Connection = cn
    'Me.Database1DataSet1.Clear()
     Me.StudentTBTableAdapter.Fill(Me.Database1DataSet1.StudentTB)
    '  'myda = New SqlDataAdapter(cmd)


End Sub

这里是完整的代码

    Imports System
Imports System.Data
Imports System.Data.SqlClient
Imports System.Data.SqlClient.SqlDataReader
Imports System.Windows.Forms

Public Class Student

    Dim cn As New SqlConnection("Data Source=(LocalDB)\v11.0;AttachDbFilename=C:\Users\Nate\documents\visual studio 2012\Projects\WindowsApplication9\WindowsApplication9\Database1.mdf;Integrated Security=True")
    Dim cmd As New SqlCommand
    Dim dr As SqlDataReader
    Private dataAdapter As New SqlDataAdapter()
    Dim gen As String
    Dim bs As New BindingSource
    Dim dt As New DataTable

    Private Sub Student_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        'TODO: This line of code loads data into the 'Database1DataSet1.avTable' table. You can move, or remove it, as needed.
        Me.AvTableTableAdapter.Fill(Me.Database1DataSet1.avTable)
        'TODO: This line of code loads data into the 'Database1DataSet1.StudentTB' table. You can move, or remove it, as needed.
        Me.StudentTBTableAdapter.Fill(Me.Database1DataSet1.StudentTB)
        cmd.Connection = cn
        Form1.Hide()



    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        If AvTableBindingSource.Position + 1 < AvTableBindingSource.Count Then
            AvTableBindingSource.MoveNext()
            Button7.PerformClick()
            ' Otherwise, move back to the first item.
        Else
            AvTableBindingSource.MoveFirst()
            Button7.PerformClick()
        End If

        ' Force the form to repaint.
        Me.Invalidate()



    End Sub


    Private Sub Button7_Click(sender As Object, e As EventArgs) Handles Button7.Click
        PictureBox1.Image = System.Drawing.Bitmap.FromFile(ID.Text)
    End Sub


    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        BDate1.Format = DateTimePickerFormat.Custom
        BDate1.CustomFormat = "MM/dd/yyyy"

        If fname.Text <> "" And lname.Text <> "" Then
            If Not cn.State = ConnectionState.Open Then
                cn.Open()
            End If
            ' cn1.Open()
            If rb1.Checked Then
                gen = rb1.Text.ToString
            ElseIf rb2.Checked Then
                gen = rb2.Text.ToString
            End If

            cmd.CommandText = "INSERT INTO StudentTB (FirstName,LastName,Birthday,Avatar,Gender,Grade) values('" & fname.Text & "', '" & lname.Text & "', '" & BDate1.Text & "', '" & AvtarNM.Text & "', '" & gen & "', '" & TxtGrade.Text & "')"
            cmd.ExecuteNonQuery()
            dt.Load(cmd.ExecuteReader())
            bs.DataSource = dt
            DataGridView1.DataSource = bs
            cn.Close()
            fname.Text = ""
            lname.Text = ""




        End If
    End Sub
    Private Sub genPCI()
        If rb1.Checked Then
            gen = rb1.Text.ToString
        ElseIf rb2.Checked Then
            gen = rb2.Text.ToString
        End If
    End Sub

    Public Function ChangeFormat(ByVal dtm As DateTime, ByVal format As String) As String
        Return dtm.ToString(format)
    End Function



    Private Sub Closestudent_Click(sender As Object, e As EventArgs) Handles Closestudent.Click
        Form1.Show()
        Me.Close()
    End Sub

    Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
        bs.EndEdit()
        dataAdapter.Update(dt)
        DataGridView1.DataSource = dt

        ' dt.Load(Command.ExecuteReader())
        'Database1DataSet1.Reset()
        'DataGridView1.Columns.Clear()
        ' DataGridView1.DataSource = Nothing
        ' Me.StudentTBTableAdapter.Fill(Me.Database1DataSet1.StudentTB)
        ' StudentTBBindingSource.ResetBindings(True)
        ' Database1DataSet1.refresh()
        ' Dim myda As String
        '  cmd.Dispose()
        ' cmd.Connection = cn
        ' StudentTBBindingSource.ResetBindings(False)
        'Database1DataSet1.StudentTB.Clear()

        '  'myda = New SqlDataAdapter(cmd)

        ' DataGridView1.DataSource = Database1DataSet1.StudentTB
    End Sub


End Class

Answer 1

你可以这样试试

Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click

    bs.EndEdit()
    dataadapter.Update(dt)
    DataGridView1.DataSource = dt

End Sub

更新

或者您可以使用绑定(bind)数据源并在您的表单类中删除它

Dim bs As New BindingSource

在 datagridview 中 .. 在 button1_click 中

Dim dt As New DataTable
dt.Load(cmd.ExecuteReader())
bs.DataSource = dt
DataGridView1.DataSource = bs

因此，如果更新，则将在 button4_click 之后显示