在gridview中删除记录后如何刷新所有标签？

Question

On the left side, I have 3 labels that display the data according to the database. I want to whenever I delete a record in the gridview, the label will automatically refresh. I do not want to click on the browser refresh button to refresh the labels. I only want to refresh the labels. I already create a method called UpdateLabel() and I put it in the grdEvent_RowUpdating and it works, whenever I edit, it will refresh the labels. But if I put the UpdateLabel() method in the grdEvent_RowDeleting , it doesn't work, why? help. help

Click delete button on gridview, and this will pop up

After clicking the ok button at the pop up.

After clicking the refresh, then the label will refresh

protected void Page_Load(object sender, EventArgs e)
    {


        if (!IsPostBack)
        {
            UpdateLabels(); // Update labels without refreshing page

            string strConnString = ConfigurationManager.ConnectionStrings["ProjectConnectionString"].ConnectionString;
            string str;
            SqlCommand com;

            SqlConnection con = new SqlConnection(strConnString);
            con.Open();
            str = "select * from EVENT_ANNOUNCE where getdate() >= STARTDATE and cast(getdate() as Date) <= ENDDATE";
            com = new SqlCommand(str, con);
            SqlDataReader reader = com.ExecuteReader();



            var events = new List<string>();

            if (reader.HasRows)
            {
                while (reader.Read())
                    events.Add(reader["EVENTNAME"].ToString());
            }

            if (events.Count >= 1)
                lblEvent1.Text = events[0];
            if (events.Count >= 2)
                lblEvent2.Text = events[1];
            if (events.Count >= 3)
                lblEvent3.Text = events[2];

            reader.Close();
            con.Close();

        }


        if (Page.IsPostBack == false)
        {
            bindEventGridView();

        }



    }

    // Update labels without refreshing page
    public void UpdateLabels()
    {

        string strConnString = ConfigurationManager.ConnectionStrings["ProjectConnectionString"].ConnectionString;
        string str;
        SqlCommand com;

        SqlConnection con = new SqlConnection(strConnString);
        con.Open();
        str = "select * from EVENT_ANNOUNCE where getdate() >= STARTDATE and cast(getdate() as Date) <= ENDDATE";
        com = new SqlCommand(str, con);
        SqlDataReader reader = com.ExecuteReader();

        var events = new List<string>();

        if (reader.HasRows)
        {
            while (reader.Read())
                events.Add(reader["EVENTNAME"].ToString());
        }

        if (events.Count >= 1)
            lblEvent1.Text = events[0];
        if (events.Count >= 2)
            lblEvent2.Text = events[1];
        if (events.Count >= 3)
            lblEvent3.Text = events[2];

        reader.Close();
        con.Close();
    }

    protected void grdEvent_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        // get row selected by user
        int selectedRow = e.RowIndex;
        int ID = (int)grdEvent.DataKeys[selectedRow].Value;
        // Delete Record
        deleteEventRecord(ID);
        UpdateLabels();
    }

    private void deleteEventRecord(int ID)
    {

        string strConnectionString =
                ConfigurationManager.ConnectionStrings["ProjectConnectionString"].ConnectionString;
        SqlConnection myConnect = new SqlConnection(strConnectionString);

        string strCommandText = "DELETE EVENT_ANNOUNCE WHERE ID=@ID";

        SqlCommand cmd = new SqlCommand(strCommandText, myConnect);
        cmd.Parameters.AddWithValue("ID", ID);

        myConnect.Open();
        int result = cmd.ExecuteNonQuery();

        if (result > 0)
        {
            lblSuccess.Visible = true;
            lblSuccess.Text = "Record deleted";
            lblError.Visible = false;
        }
        else
        {
            lblError.Visible = true;
            lblError.Text = "Update fail";
            lblSuccess.Visible = false;
        }

        bindEventGridView();
        myConnect.Close();

    }

    protected void grdEvent_RowEditing(object sender, GridViewEditEventArgs e)
    {
        grdEvent.EditIndex = e.NewEditIndex;
        bindEventGridView();
    }

    protected void grdEvent_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        int selectedRow = e.RowIndex;   //get selected row
        //  get product id from data key
        int id = (int)grdEvent.DataKeys[selectedRow].Value;

        //  get current grid view row
        GridViewRow row = (GridViewRow)grdEvent.Rows[selectedRow];
        TextBox eventtype = (TextBox)row.FindControl("txtEventType");
        //  find text box for txtPrice
        TextBox eventname = (TextBox)row.FindControl("txtEventName");
        TextBox startdate = (TextBox)row.FindControl("txtStartDate");
        TextBox enddate = (TextBox)row.FindControl("txtEndDate");
        //  Remove $ sign
        string strEventType = eventtype.Text;
        string strEventName = eventname.Text;
        string strStartDate = startdate.Text;
        string strEndDate = enddate.Text;
        DateTime datStartDate;
        DateTime datEndDate;
        if (DateTime.TryParseExact(strStartDate, new string[] { "dd/MM/yyyy" },
                               System.Globalization.CultureInfo.InvariantCulture,
                               System.Globalization.DateTimeStyles.None, out datStartDate)
    &&
    DateTime.TryParseExact(strEndDate, new string[] { "dd/MM/yyyy" },
                               System.Globalization.CultureInfo.InvariantCulture,
                               System.Globalization.DateTimeStyles.None, out datEndDate)
   )
        {
            updateEventGridviewRecord(id, strEventType, strEventName, datStartDate, datEndDate);
        }

            /*
             || DateTime.TryParseExact(strEndDate, new string[] { "dd/MM/yyyy" },
                               System.Globalization.CultureInfo.InvariantCulture,
                               System.Globalization.DateTimeStyles.None, out datEndDate
             */

        else
        {
            lblError.Visible = true;
            lblError.Text = "Invalid Date";
            lblSuccess.Visible = false;
        }
        UpdateLabels();
    }

    private void updateEventGridviewRecord(int id, string strEventType, string strEventName, DateTime datStartDate, DateTime datEndDate)
    {
        try
        {
            string strConnectionString = ConfigurationManager.ConnectionStrings["ProjectConnectionString"].ConnectionString;
            SqlConnection myConnect = new SqlConnection(strConnectionString);

            string strCommandText = "UPDATE EVENT_ANNOUNCE SET [EVENTTYPE]=@EVENTTYPE, [EVENTNAME]=@EVENTNAME, [STARTDATE]=@STARTDATE, [ENDDATE]=@ENDDATE WHERE [ID]=@ID";

            SqlCommand cmd = new SqlCommand(strCommandText, myConnect);
            cmd.Parameters.AddWithValue("@id", id);
            cmd.Parameters.AddWithValue("@EVENTTYPE", strEventType);
            cmd.Parameters.AddWithValue("@EVENTNAME", strEventName);
            cmd.Parameters.AddWithValue("@STARTDATE", datStartDate);
            cmd.Parameters.AddWithValue("@ENDDATE", datEndDate);
            myConnect.Open();

            int result = cmd.ExecuteNonQuery();

            if (result > 0)
            {
                lblSuccess.Visible = true;
                lblSuccess.Text = "Record updated!";
                lblError.Visible = false;
            }
            else
            {
                lblSuccess.Visible = true;
                lblError.Text = "Update fail";
                lblError.Visible = false;
            }

            myConnect.Close();


            //Cancel Edit Mode
            grdEvent.EditIndex = -1;
            bindEventGridView();
        }

        catch
        {
            lblError.Visible = true;
            lblError.Text = "Please Enter Approximate data";
            lblSuccess.Visible = false;
        }
    }

Answer 1

Wrap your labels on the left panel in their own an update panel.

<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:Label ID="LabelEvent1" runat="server" Width="99%" />
<asp:Label ID="LabelEvent2" runat="server" Width="99%" />
<asp:Label ID="LabelEvent3" runat="server" Width="99%" />
   </contenttemplate>
</asp:UpdatePanel>

In your row deleted event call your updateLabels method

 protected void grdEvent_RowDeleted(object sender, GridViewEditEventArgs e)
{
   if(e.Exception == null)
{
    UpdateLabels();
}
}