Question

我知道这是一个古老的话题，但我找到的解决方案似乎都没有帮助。我是新来的，所以请指导我：我正在调用数据库来检索记录，然后将其与复选框一起显示在gridview中。单击该复选框时，我需要将选中的行记录与insert语句中的其他查询信息一起保存到单独的表中。问题是firstname和lastname没有填充，导致null异常。任何人都可以查看这个并让我知道如何解决它？

Imports System.Data
Imports System.Data.SqlClient
Imports System.Web.UI.WebControls
Partial Class scores
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
    Me.GridView1.DataBind()
End Sub
Protected Sub Save_Click(sender As Object, e As EventArgs) Handles Save.Click
    For Each row As GridViewRow In GridView1.Rows
        Dim chkrow As CheckBox = DirectCast(row.FindControl("cb1"), CheckBox)
        If chkrow.Checked = True Then
            Dim firstname As TextBox = DirectCast(row.FindControl("firstname"), TextBox)
            Dim lastname As TextBox = DirectCast(row.FindControl("lastname"), TextBox)
            Dim conn As New SqlClient.SqlConnection
            Dim cmd As SqlClient.SqlCommand = New SqlClient.SqlCommand()
            conn.ConnectionString = "Data Source=SERVERNAME;Persist Security Info=True;User ID=ME;Password=PASSWORD;Initial Catalog=Testing"
            cmd.Connection = conn
            cmd.CommandText = "insert into scores (date, test, score, personid, testid) Values (getdate(), @test, @score, (select personid from persons where firstname = '" + firstname.Text + "' and lastname = '" + lastname.Text + "'), (select testid from tests where testnm ='" + DDL2.SelectedValue + "'))"
            conn.Open()
            Try
                cmd.Parameters.Add("@test", SqlDbType.NVarChar).Value = DDL2.SelectedValue
                cmd.Parameters.Add("@score", SqlDbType.NVarChar).Value = Score.Text
                cmd.ExecuteNonQuery()
                Response.Write("Saved")
            Catch ex As System.Data.SqlClient.SqlException
                MsgBox(ex.Message)
                conn.Close()
            End Try
            Exit For
        End If
    Next
End Sub

结束班

标记页面：

 <%@ Page Language="VB" AutoEventWireup="false" CodeFile="scores.aspx.vb" Inherits="scores" %>

    <!DOCTYPE html>

    <html xmlns="http://www.w3.org/1999/xhtml">
    <head runat="server">
        <title></title>
    </head>
    <body>
        <form id="form1" runat="server">
        <div>

            Scores<br /><br />
            Pick tester name <asp:GridView ID="GridView1" runat="server"    AutoGenerateColumns="False" DataKeyNames="personid" 
DataSourceID="SqlDataSource1">
                <Columns>
                    <asp:TemplateField>
                        <ItemTemplate>
                            <asp:CheckBox ID="CB1" runat="server" />
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:BoundField DataField="personid" HeaderText="personid" InsertVisible="False" ReadOnly="True" SortExpression="personid" />
                    <asp:BoundField DataField="Firstname" HeaderText="Firstname" SortExpression="Firstname" />
                    <asp:BoundField DataField="Lastname" HeaderText="Lastname" SortExpression="Lastname" />
                    <asp:BoundField DataField="Social" HeaderText="Social" SortExpression="Social" />
                </Columns>
            </asp:GridView>
            <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:Testing %>" SelectCommand="SELECT [personid], [Firstname], [Lastname], [Social] FROM [Persons] where [personid] not in (select personid from scores) ORDER BY [Lastname]  "></asp:SqlDataSource>
            Test taken <asp:DropDownList ID="DDL2" runat="server" DataSourceID="SqlDataSource2" DataTextField="TestNM" DataValueField="TestNM"></asp:DropDownList>
            <asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ ConnectionStrings:Testing %>" SelectCommand="SELECT [TestNM], [testid] FROM [Tests] ORDER BY [TestNM]"></asp:SqlDataSource>
            Score <asp:TextBox ID="Score" runat="server"></asp:TextBox><br />
            <asp:Button ID="Save" runat="server" Text="Save" />
        </div>
        </form>
    </body>
    </html>

Answer 1

在我尝试阅读之前，它看起来像是在重新绑定所有数据（在Page_Load中）。首先尝试检查回发：

If Not Page.IsPostback Then
    Me.GridView1.DataBind()
End If

从gridview复选框获取行值

1 个答案: