我有一个显示问题列表的gridview。只有一个字段是可编辑的,并且如果信息已被编辑,则电子邮件被发送到特定的“命运”。所有工作正常,但是当我尝试在我的SendEmail函数中使用Findcontrol时,我得到 “对象引用未设置为对象的实例”。我如何获得问题ID?在gridview行更新后获取值
我的SqlDataSource:
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:conn %>" SelectCommand="SELECT Questions.QuestionID, Questions.Name, Questions.Question, Questions.Destiny, Questions.DateQuestion, Questions.Answer" UpdateCommand="UPDATE Questions SET Destiny = @Destiny WHERE (QuestionID = @QuestionID)">
<SelectParameters>
</SelectParameters>
<UpdateParameters>
<asp:Parameter Name="Destiny" />
<asp:Parameter Name="QuestionID" />
</UpdateParameters>
</asp:SqlDataSource>
我的GridView:
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="QuestionID" OnRowUpdated="GridView1_RowUpdated"
DataSourceID="SqlDataSource1">
<Columns>
<asp:TemplateField HeaderText="ID" InsertVisible="False" SortExpression="QuestionID">
<ItemTemplate>
<asp:Label ID="LabelQuestionID" runat="server" Text='<%# Bind("QuestionID") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Question" InsertVisible="False" SortExpression="Question">
<ItemTemplate>
<asp:Label ID="LabelQuestion" runat="server" Text='<%# Bind("Question") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Date" SortExpression="DateQuestion">
<ItemTemplate>
<asp:Label ID="LabelDateQuestion" runat="server" Text='<%# Bind("DateQuestion", "{0:g}") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Destiny" SortExpression="Destiny">
<ItemTemplate>
<asp:Label ID="LabelDestiny" runat="server" Text='<%# Bind("Destiny") %>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="TextBox3" runat="server" Text='<%# Bind("Destiny") %>'></asp:TextBox>
</EditItemTemplate>
</asp:TemplateField>
<asp:TemplateField ShowHeader="False">
<EditItemTemplate>
<asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="True" CommandName="Update"
Text="Update"></asp:LinkButton>
<asp:LinkButton ID="LinkButton3" runat="server" CausesValidation="False" CommandName="Cancel"
Text="Cancel"></asp:LinkButton>
</EditItemTemplate>
<ItemTemplate>
<asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="False" CommandName="Edit" Text="Edit"></asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
我身后代码:
Protected Sub GridView1_RowUpdated(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewUpdatedEventArgs)
If Trim(e.OldValues("Destiny").ToString <> Trim(e.NewValues("Destiny").ToString)) Then
QuestionID = GridView1.FindControl("LabelQuestionID").ToString
SendEmailtoAdviser(Trim(e.NewValues("Destiny")), QuestionID)
End If
End Sub
嗨,谢谢你的帮助。我不确定我的答案需要做什么。 – netNewbi3 2010-06-29 10:51:44
@ netNewbi3 - 一旦你分离了你的代码,你可以通过调试器来找出哪一行实际上引发了空引用异常。例如,它*可能是'FindControl'返回'null'。有了这些信息,你就可以明白为什么会出现这种情况。是标签名称不正确,还是您在标签的错误容器中查找? – ChrisF 2010-06-29 11:04:35
ChrisF,谢谢。标签名称是正确的。我如何检查我是否在标签的错误容器中查找? – netNewbi3 2010-06-29 11:19:11