Question

我正在开发一个asp.net VB网页。我创建了一个网格视图，它将在按钮单击事件中添加数据，但在第一个按钮单击事件中，它会在网格视图中添加两行，并且在第一个按钮单击情形正常后。如何在第一次活动中避免这种重复？

这里我附上了代码和一个屏幕打印。我需要避免使用空值的行。

Imports System.Data
Imports System.Data.SqlClient 
Imports System.Collections
Partial Class add_stock
Inherits System.Web.UI.Page

Private numOfColumns As Integer = 1
Private ctr As Integer = 0
Private tablepanel As Table = Nothing


Dim row As New TableRow()
Dim cell As New TableCell()
Dim tb9 As New Button
Dim panel2 As New Panel
Dim DT As New DataTable


Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not IsPostBack Then
        tablepanel = New Table()
        tablepanel.ID = "tableBuild"
        Session("table") = tablepanel
        ViewState("ctr") = ctr
        'BindGridview()
    End If
    ctr = CType(ViewState("ctr"), Int32)
    tablepanel = DirectCast(Session("table"), Table)
    Panel1.Controls.Add(tablepanel)

    DT.Columns.Add("ID")
    DT.Columns.Add("Name")
    DT.Columns(0).AutoIncrement = True

End Sub

Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim drCurrentRow As DataRow = Nothing
    If GridView1.Rows.Count > 1 Then
        AddNewRow()
    ElseIf GridView1.Rows.Count = 1 Then
        AddNewRow()
    Else
        BindGridview()
        AddNewRow()
    End If
    'Place the table with textboxes on the page
    '-------- numOfColumns = 1
    '-------- GenerateTable(numOfColumns)
    'End of the table display with textboxes 

    ' Add row to grid view
End Sub

Protected Sub Button2_Click(ByVal sender As Object, ByVal e As EventArgs)
    ClientScript.RegisterStartupScript(Me.GetType, "Button_Alert", "alert('Button clicked!');", True)
    numOfColumns = 1
    'Generate the Table based from the inputs
    GenerateTable(numOfColumns)
End Sub
Protected Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
    GridView1.ShowFooter = True
End Sub

Protected Sub BindGridview()
    Dim dt As New DataTable()
    'dt.Columns.Add("rowid", GetType(Integer))
    dt.Columns.Add("Item Number", GetType(String))
    dt.Columns.Add("Item Category", GetType(String))
    dt.Columns.Add("Lead Time", GetType(String))
    dt.Columns.Add("Supplier", GetType(String))
    dt.Columns.Add("Item Quantity", GetType(String))
    dt.Columns.Add("Re-order Level", GetType(String))
    dt.Columns.Add("Unit Price", GetType(String))
    dt.Columns.Add("Retails Price", GetType(String))
    dt.Columns.Add("Item Details", GetType(String))
    Dim dr As DataRow = dt.NewRow()
    dr("Item Number") = String.Empty
    dr("Item Category") = String.Empty
    dr("Lead Time") = String.Empty
    dr("Supplier") = String.Empty
    dr("Item Quantity") = String.Empty
    dr("Re-order Level") = String.Empty
    dr("Unit Price") = String.Empty
    dr("Retails Price") = String.Empty
    dr("Item Details") = String.Empty
    dt.Rows.Add(dr)
    ViewState("Curtbl") = dt
    GridView1.DataSource = dt
    'GridView1.DataBind()
End Sub

Private Sub AddNewRow()

    Dim rowIndex As Integer

    If ViewState("Curtbl") IsNot Nothing Then
        Dim dt As DataTable = DirectCast(ViewState("Curtbl"), DataTable)
        Dim drCurrentRow As DataRow = Nothing
        If dt.Rows.Count > 1 Then
            Dim rowcount As Integer = dt.Rows.Count
            drCurrentRow = dt.NewRow()
            '   drCurrentRow("rowid") = rowcount + 1
            dt.Rows(rowcount - 1)("Item Number") = TextBox21.Text
            dt.Rows(rowcount - 1)("Item Category") = DropDownList4.Text
            dt.Rows(rowcount - 1)("Lead Time") = TextBox19.Text
            dt.Rows(rowcount - 1)("Supplier") = DropDownList3.Text
            dt.Rows(rowcount - 1)("Item Quantity") = TextBox22.Text
            dt.Rows(rowcount - 1)("Re-order Level") = TextBox17.Text
            dt.Rows(rowcount - 1)("Unit Price") = TextBox23.Text
            dt.Rows(rowcount - 1)("Retails Price") = TextBox20.Text
            dt.Rows(rowcount - 1)("Item Details") = TextBox18.Text
            dt.Rows.Add()
            rowIndex += 1
            ViewState("Curtbl") = dt
            GridView1.DataSource = dt
            GridView1.DataBind()
            MsgBox("1st")

        ElseIf dt.Rows.Count = 1 Then
            Dim rowcount As Integer = dt.Rows.Count
            'drCurrentRow = dt.NewRow()
            '   drCurrentRow("rowid") = rowcount + 1
            MsgBox(rowcount + 1)
            dt.Rows(rowcount - 1)("Item Number") = TextBox21.Text
            dt.Rows(rowcount - 1)("Item Category") = DropDownList4.Text
            dt.Rows(rowcount - 1)("Lead Time") = TextBox19.Text
            dt.Rows(rowcount - 1)("Supplier") = DropDownList3.Text
            dt.Rows(rowcount - 1)("Item Quantity") = TextBox22.Text
            dt.Rows(rowcount - 1)("Re-order Level") = TextBox17.Text
            dt.Rows(rowcount - 1)("Unit Price") = TextBox23.Text
            dt.Rows(rowcount - 1)("Retails Price") = TextBox20.Text
            dt.Rows(rowcount - 1)("Item Details") = TextBox18.Text
            dt.Rows.Add()
            rowIndex += 1

            ViewState("Curtbl") = dt
            GridView1.DataSource = dt
            GridView1.DataBind()
            MsgBox("2nd")
        Else
            Dim rowcount As Integer = dt.Rows.Count
            drCurrentRow = dt.NewRow()
            '  drCurrentRow("rowid") = rowcount + 1
            dt.Rows(1)("Item Number") = TextBox21.Text
            dt.Rows(1)("Item Category") = DropDownList4.Text
            dt.Rows(1)("Lead Time") = TextBox19.Text
            dt.Rows(1)("Supplier") = DropDownList3.Text
            dt.Rows(1)("Item Quantity") = TextBox22.Text
            dt.Rows(1)("Re-order Level") = TextBox17.Text
            dt.Rows(1)("Unit Price") = TextBox23.Text
            dt.Rows(1)("Retails Price") = TextBox20.Text
            dt.Rows(1)("Item Details") = TextBox18.Text
            dt.Rows.Add()
            rowIndex += 1
            ViewState("Curtbl") = dt
            GridView1.DataSource = dt
            GridView1.DataBind()
            MsgBox("3rd")
        End If
    Else
        Response.Write("ViewState Value is Null")
    End If

End Sub


Protected Sub OnRowDeleting(sender As Object, e As GridViewDeleteEventArgs)

    Dim dt As DataTable = TryCast(ViewState("Curtbl"), DataTable)
    Dim RowToDelete As Integer = e.RowIndex

    If dt.Rows.Count > 0 Then
        dt.Rows.RemoveAt(RowToDelete)
        dt.AcceptChanges()
        GridView1.DataSource = dt
    End If
    GridView1.DataBind()
End Sub

Protected Sub OnRowDataBound(sender As Object, e As GridViewRowEventArgs)
    If e.Row.RowType = DataControlRowType.DataRow Then
        Dim item As String = e.Row.Cells(0).Text
        For Each button As Button In e.Row.Cells(2).Controls.OfType(Of Button)()
            If button.CommandName = "Delete" Then
                button.Attributes("onclick") = "if(!confirm('Do you want to delete " + item + "?')){ return false; };"
            End If
        Next
    End If
End Sub 
End Class

enter image description here

Answer 1

在上面的代码中，您只需要注释AddNewRow（）方法，就像在BindGridView（）中一样，您正在为表创建新行并将其绑定到Grid，因此无需在此处调用AddNewRow（）。请查看以下代码。

Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim drCurrentRow As DataRow = Nothing
    If GridView1.Rows.Count > 1 Then
        AddNewRow()
    ElseIf GridView1.Rows.Count = 1 Then
        AddNewRow()
    Else
        BindGridview()
        'AddNewRow()
    End If
    'Place the table with textboxes on the page
    '-------- numOfColumns = 1
    '-------- GenerateTable(numOfColumns)
    'End of the table display with textboxes 

    ' Add row to grid view
End Sub

如何避免VB ASP GridView中的重复？

1 个答案: