Dynamic buttons in GridView - Button.Click event not firing_问答_开发者

I have a GridView control bound to an AccessDataSource. After selecting a row I'm creating a table inside the selected row. I'm adding Buttons to this table. Their Click event never gets fired. I read about recreating the buttons and stuff, but still no luck solving the issue. Thanks for help!

.aspx:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="AdminSurvey.aspx.cs" Inherits="AdminSurvey" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
   <title></title>
</head>
<body>
<form id="form1" runat="server">
<asp:GridView ID="id_survey_grid_view" runat="server" DataSourceID="id_access_data_source"  
              SkinID="default_skin" AllowSorting="True" AutoGenerateColumns="false" 
              OnRowCreated="SurveyGridView_RowCreated">
<Columns>
        <asp:HyperLinkField HeaderText="Title" SortExpression="TITLE"
            DataTextField="TITLE" DataNavigateUrlFields="SURVEY_ID"
            DataNavigateUrlFormatString="~\AdminSurvey.aspx?survey_id={0}">
        </asp:HyperLinkField>
    </Columns>
</asp:GridView>
<asp:AccessDataSource ID="id_access_data_source" runat="server" DataFile="~/App_Data/database.mdb" 
    OldValuesParameterFormatString="original_{0}"
    OnLoad="InitAccessDataSource">
</asp:AccessDataSource>
</form>
</body>
</html>

.cs:

public partial class AdminSurvey : System.Web.UI.Page
{
 private const string ID_BUTTON_SUBMIT = "SUBMIT_BUTTON";
 private const string ID_BUTTON_DELETE = "SUBMIT_DELETE";
 private string _selected_survey;

protected void SurveyGridView_RowCreated(Object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow && e.Row.DataItem != null && !IsPostBack)
    {
        string survey = ((DataRowView)e.Row.DataItem).Row.ItemArray[0].ToString();
        if (survey.Equals(_selected_survey))
        {
            e.Row.Cells[0].Controls.Clear();
            // create table
            e.Row.Cells[0].Controls.Add(createSurveyTable(((DataRowView)e.Row.DataItem).Row.ItemArray[0].ToString(),
                                                    ((DataRowView)e.Row.DataItem).Row.ItemArray[1].ToString(),
                                                    ((DataRowView)e.Row.DataItem).Row.ItemArray[2].ToString()));

            ViewState["row_index"] = Convert.ToString(e.Row.RowIndex);
            ViewState["survey_id"] = ((DataRowView)e.Row.DataItem).Row.ItemArray[0].ToString();
            ViewState["title"] = ((DataRowView)e.Row.DataItem).Row.ItemArray[1].ToString();
            ViewState["description"] = ((DataRowView)e.Row.DataItem).Row.ItemArray[2].ToString();
        }
    } else if(e.Row.RowType == DataControlRowType.DataRow && e.Row.DataItem != null && IsPostBack) {
        string row_idx = (string)ViewState["row_index"];

        if (row_idx != null && e.Row.RowIndex.Equals(Convert.ToInt32(row_idx)))
        {
            _selected_survey = (string)ViewState["survey_id"];
            string title = (string)ViewState["title"];
            string description = (string)ViewState["description"];

            e.Row.Cells[0].Controls.Clear();
            // recreate table
            e.Row.Cells[0].Controls.Add(createSurveyTable(_selected_survey, title, description));
        }
    }
}

private Table createSurveyTable(string survey_id, string title, string description)
{
    Table table = new Table();
    TableRow row = new TableRow();
    TableCell cell = new TableCell();

    Table questions_table = createQuestionsTable(survey_id);

    cell.Controls.Add(questions_table);

    row.Cells.Add(cell);
    table.Rows.Add(row);

    return table;
}

private Table createQuestionsTable(string survey_id)
{

   开发者_如何转开发 // submit row
    TableRow submit_row = new TableRow();
    TableCell submit_cell = new TableCell();

    submit_button = new Button();
    submit_button.Text = "Submit";
    submit_button.ID = ID_BUTTON_SUBMIT;
    submit_button.Click += new EventHandler(submitButton_Click);
    submit_cell.Controls.Add(submit_button);

    delete_button = new Button();
    delete_button.Text = "Delete";
    delete_button.ID = ID_BUTTON_DELETE;
    delete_button.Click += new EventHandler(deleteButton_Click);
    submit_cell.Controls.Add(delete_button);

    submit_row.Cells.Add(submit_cell);
    table.Rows.Add(submit_row);

    return table;
}

private void submitButton_Click(object sender, EventArgs e)
{
}

private void deleteButton_Click(object sender, EventArgs e)
}

} // class

I hate to answer my question, but I hope it saves anyone time when looking at the problem. It turned out, that the error was in the if conditions:

if (e.Row.RowType == DataControlRowType.DataRow && e.Row.DataItem != null && !IsPostBack)
{
    // ...
} else if (e.Row.RowType == DataControlRowType.DataRow && e.Row.DataItem != null && IsPostBack) {
    // ...
}

e.Row.DataItem != null was erroneously present in both conditions and the second condition, with IsPostBack equal to true, was never executed.

The correct code is:

if (e.Row.RowType == DataControlRowType.DataRow && e.Row.DataItem != null && !IsPostBack)
{
    // ...
} else if (e.Row.RowType == DataControlRowType.DataRow && IsPostBack)
{
    // ...
}

Try assigning a command name, and attach to the RowCommand event of the grid to listen for the click of the button, as an alternative to tapping into the click event.