如何清除gridview？

Question

我正在创建一个动态gridview函数,它将DB中的不同表绑定到数据表中,然后将数据表分配给gridview!这是它的工作原理,我有一个下拉列表,gridview和一个按钮,该按钮将根据下拉列表选择触发特定功能,然后gridview将绑定数据,我的问题是,当你第一次按下按钮时, gridview将绑定来自DB的数据,第二次按下,gridview将从第一次按下的数据中复制数据!如何清除gridview以避免数据重复？

Private Sub Login()
    sSql = "" & _
    "SELECT TYPE, SUBTYPE, LOGTS, ACTION, USERID, STAT1 " & _
    "FROM i_LOG " & _
    "WHERE TYPE = 'USR' AND SUBTYPE = 'LOG' " & _
    "AND CONVERT(VARCHAR(20), LOGTS, 103) >= '" & txtDTFrom.Text & _
    "' AND CONVERT(VARCHAR(20), LOGTS, 103) <= '" & txtDTTo.Text & "'"

    DT = CreateDataTable(sSql)     'Retrieve from database.

    Session(sSesDT) = DT
    GVM.DataTable = DT
    GVM.GVAddEmptyRow()

    Dim seq As New BoundField
    Dim Type As New BoundField
    Dim SubType As New BoundField
    Dim Logts As New BoundField
    Dim action As New BoundField
    Dim user As New BoundField
    Dim status As New BoundField

    seq.HeaderText = GVM.DTNumberField
    seq.DataField = GVM.DTNumberField

    Type.HeaderText = "Type"
    Type.DataField = "TYPE"

    SubType.HeaderText = "Subtype"
    SubType.DataField = "SUBTYPE"

    Logts.HeaderText = "Date and Time"
    Logts.DataField = "LOGTS"

    action.HeaderText = "Action"
    action.DataField = "ACTION"

    user.HeaderText = "User ID"
    user.DataField = "USERID"

    status.HeaderText = "Status"
    status.DataField = "STAT1"

    gv.AutoGenerateColumns = False
    gv.Columns.Add(Type)
    gv.Columns.Add(SubType)
    gv.Columns.Add(Logts)
    gv.Columns.Add(action)
    gv.Columns.Add(user)
    gv.Columns.Add(seq)
    gv.Columns.Add(status)

    gv.DataSource = Session(sSesDT)
    gv.DataBind()
End Sub

Private Overloads Function CreateDataTable(ByVal sSql As String) As DataTable
    Dim DA As New OleDb.OleDbDataAdapter
    Dim dtDataTbl As New DataTable
    Dim dcDataCol As New DataColumn

    With DBMgr
        .openCnn()
        .SQL = sSql
        .openRst()
        DA.Fill(dtDataTbl, .rst)
    End With

    '==Adding Columns==
    dcDataCol = New DataColumn  'No
    With dcDataCol
        .DataType = GetType(Int32)
        .ColumnName = GVM.DTNumberField
        .AutoIncrement = True
        '.AllowDBNull = True
    End With
    dtDataTbl.Columns.Add(dcDataCol)
    '**Adding Columns**

    Return dtDataTbl
End Function

Answer 1

抱歉,这是在C#中,但只是在绑定任何新数据之前调用它并且它将清除所有现有数据......除非问题是您分配的数据源具有重复数据.

gridview.DataSource=null;
gridview.DataBind();

另外,请注意,每次调用该过程时都要添加每一列？你需要运行:

gridview.Columns.Clear();