转发器按钮发回到page_load而不是我的方法？

Question

In an aspx page I have the following repeater:

<asp:Repeater runat="server" ID="r" OnItemCommand="paper_ItemCommand">
    <ItemTemplate>
        <div style="padding-bottom:20px">
            <asp:HiddenField runat="server" ID="questionID" Value='<%# Eval("ID") %>'/>
            <asp:Label runat="server" ID="questionNumber" Text='<%# Eval("Number") %>'/><br />
            <asp:Label runat="server" ID="question1" Text='<%# Eval("Question1") %>' /><br />
            [ <asp:Label runat="server" ID="questionMark" Text='<%# Eval("Mark") %>'/> ]<br />
            <asp:Button ID="View_Conversations" runat="server" Text="View Conversations" CommandName="ViewConversationsCommand" />
        </div>
    </ItemTemplate>
    <SeparatorTemplate>
        <hr />
    </SeparatorTemplate>
</asp:Repeater>

And in the code behind file I have the following methods:

    protected void Page_Load(object sender, EventArgs e)
    {
        var paperID = Session["paperID"].ToString();
        QuestionPaper = repository.GetPaper(Int32.Parse(paperID));
        r.DataSource = QuestionPaper.Questions;
        r.DataBind();
    }

    protected void paper_ItemCommand(object sender, RepeaterCommandEventArgs e)
    {
        switch (e.CommandName)
        {
            case "ViewConversationsCommand":
                var hidden = e.Item.FindControl("questionID") as HiddenField;
                var myquestionID = hidden.Value;
                break;
        }
    }

The problem I have is when I click the View Conversation button on the repeater, the code hits the page_load method instead of my paper_ItemCommand method. What am I getting wrong here?

Answer 1

The page load occurs because each time when you hits the button the postback occur to the page it self and its the whole page lifecycle get run. If you want to prevent not to execute the page load stuff on button click you can try as follows:

protected void Page_Load(object sender, EventArgs e)
{
    if(!IsPostBack){
      // Your existing stuff
    }
}

Good Luck !!

Answer 2

Every time a page is loaded, including when you post back to the page (say, by clicking a Button ), the Page_Load event handler will be hit. The key is to check the Page object's IsPostBack property:

protected void Page_Load(object sender, EventArgs e)
{
    if (!Page.IsPostBack) 
    {
        // do things that only should be done on the first page load
        var paperID = Session["paperID"].ToString();
        QuestionPaper = repository.GetPaper(Int32.Parse(paperID));
        r.DataSource = QuestionPaper.Questions;
        r.DataBind();
    }
}

Answer 3

page_load always run first http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vbcon/html/vbconwebformspageprocessingstages.asp test if not postback set your initialization

if(!Page.IsPostback)
{
 var paperID = Session["paperID"].ToString(); 
        QuestionPaper = repository.GetPaper(Int32.Parse(paperID)); 
        r.DataSource = QuestionPaper.Questions; 
        r.DataBind(); 
}