你好，我是vb.net编程的初学者，在使用textbox搜索或过滤datagridview时遇到了问题。我有一个用于搜索的文本框和一个用于检索值（即学生和车辆）的两个按钮。当点击student按钮时，显示student的数据，与vehicle相同，但当我将“dim dtaset as new datatable”移到students、vehicle和searchtxt事件之外时，搜索成功地过滤了数据值的数据，移动后也有问题，当单击该按钮时，它会将该按钮的数据添加到datagridview中，但当另一个按钮在第一个按钮之后单击时，数据不会替换上一个按钮，它只会添加将扩展datagrid列的列。这是我的密码提前谢谢

Private Sub searchtxt_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles searchtxt.TextChanged
    con.ConnectionString = "server=localhost;userid=root;password=1234;database=dat"

    Dim dtaset As New DataTable

    Dim DV As New DataView(dtaset)
    DV.RowFilter = String.Format("FirstName Like '%{0}%'", searchtxt.Text)
    DataGridView1.DataSource = DV
End Sub

Public Sub studattenprint()
    con.ConnectionString = "server=localhost;userid=root;password=1234;database=dat"

    Dim adpter As New MySqlDataAdapter
    Dim dtaset As New DataTable
    Dim bsource As New BindingSource

    Try
        con.Open()
        Dim query As String
        query = "select idno as 'Student_ID',lastxt as 'LastName',firstxt as 'FirstName',middletxt as 'MiddleName',log as 'Status',timein as 'Timein',crse as 'Course',dates as 'Date' from dat.studdailyhistory"
        cmd = New MySqlCommand(query, con)

        adpter.SelectCommand = cmd
        adpter.Fill(dtaset)
        If dtaset.Rows.Count >= 0 Then
            numlog.Text = dtaset.Rows.Count.ToString()
        End If
        bsource.DataSource = dtaset
        DataGridView1.DataSource = bsource

        ''DataGridView Design
        DataGridView1.AllowUserToAddRows = False ' Disabled or hide (*) Symbol...

        DataGridView1.RowHeadersVisible = False 'To hide Left indicator..
        DataGridView1.DefaultCellStyle.SelectionBackColor = Color.SteelBlue  'Selection backcolor....
        DataGridView1.AlternatingRowsDefaultCellStyle.BackColor = Color.LightGoldenrodYellow 'Alternating Backcolor.
        DataGridView1.AllowUserToResizeRows = False 'Disabled  row resize...
        DataGridView1.ReadOnly = True
        DataGridView1.MultiSelect = False
        DataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect
        DataGridView1.ShowRowErrors = False
        DataGridView1.ShowCellErrors = False
        DataGridView1.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.DisplayedCells
        DataGridView1.Sort(DataGridView1.Columns(7), System.ComponentModel.ListSortDirection.Descending)

        adpter.Update(dtaset)
        con.Close()

    Catch ex As Exception
        MessageBox.Show(ex.Message)
    Finally
        con.Dispose()
    End Try
End Sub

Public Sub vehicattenprint()
    con = New MySqlConnection
    con.ConnectionString = "server=localhost;userid=root;password=1234;database=dat"
    Dim SDA As New MySqlDataAdapter
    Dim dtaset As New DataTable
    Dim bSource As New BindingSource

    Try

        con.Open()
        Dim query As String

        query = "select tag_no as 'Tag_No.',platenum as 'Plate no.',ownername as 'Owner_name',log as 'Status',timelog as 'Time_log',dates as 'Date' from dat.vehicdailyhistory"
        cmd = New MySqlCommand(query, con)
        SDA.SelectCommand = cmd
        SDA.Fill(dtaset)
        bSource.DataSource = dtaset
        DataGridView1.DataSource = bSource

        If dtaset.Rows.Count > 0 Then
            numlog.Text = dtaset.Rows.Count.ToString()
        End If

        SDA.Update(dtaset)
        DataGridView1.AllowUserToAddRows = False ' Disabled or hide (*) Symbol...

        DataGridView1.RowHeadersVisible = False 'To hide Left indicator..
        DataGridView1.DefaultCellStyle.SelectionBackColor = Color.SteelBlue  'Selection backcolor....
        DataGridView1.AlternatingRowsDefaultCellStyle.BackColor = Color.LightGoldenrodYellow 'Alternating Backcolor.
        DataGridView1.AllowUserToResizeRows = False 'Disabled  row resize...
        DataGridView1.ReadOnly = True
        DataGridView1.MultiSelect = False
        DataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect
        DataGridView1.ShowRowErrors = False
        DataGridView1.ShowCellErrors = False
        DataGridView1.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.DisplayedCells
        DataGridView1.Sort(DataGridView1.Columns(5), System.ComponentModel.ListSortDirection.Descending)

        con.Close()
    Catch ex As Exception
        MessageBox.Show(ex.Message)
    Finally
        con.Dispose()
    End Try
End Sub

Private Sub vehicatten_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles vehicatten.Click
    vehicattenprint()
End Sub

Private Sub studatten_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles studatten.Click
    studattenprint()
End Sub