How to refresh Gridview after pressed a button in

I am trying to make a simple library database. I list the search results in a gridview, then i have a textbox and a button, user enters the isbn and clicks loan button. Then, if there is enough number of items (itemNumber>0) it is loaned by user. Here is the screenshot of user interface:

My question is, when user clicks loan button the loan may or may not be succesful. In both cases, i print a message indicating whether loan is succesful or not, and i also want the updated gridview to be displayed. The problem is, after pressing the loan button the gridview disappears and i just see the textbox, button and the message on the screen. How can i show the updated version of gridview after pressing loan button?

Here is the code file:

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

<!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">
<div>

</div>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" 
    DataKeyNames="ISBN" DataSourceID="SqlDataSource1" 
    onselectedindexchanged="GridView1_SelectedIndexChanged" 
    onrowcommand="GridView1_RowCommand">
    <Columns>
        <asp:BoundField DataField="Title" HeaderText="Title" SortExpression="Title" />
        <asp:BoundField DataField="ISBN" HeaderText="ISBN" ReadOnly="True" 
            SortExpression="ISBN" />
        <asp:BoundField DataField="AuthorName" HeaderText="AuthorName" 
            SortExpression="AuthorName" />
        <asp:BoundField DataField="AuthorlName" HeaderText="AuthorlName" 
            SortExpression="AuthorlName" />
        <asp:BoundField DataField="ItemType" HeaderText="ItemType" 
            SortExpression="ItemType" />
        <asp:BoundField DataField="PublishYear" HeaderText="PublishYear" 
            SortExpression="PublishYear" />



        <asp:BoundField DataField="numOfCopies" HeaderText="Number of Copies" 
            SortExpression="numOfCopies" />



    </Columns>
</asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" 
    ConnectionString="<%$ ConnectionStrings:ConnectionString %>" 
    SelectCommand="SELECT * FROM [Items] WHERE ([Title] LIKE '%' + @Title + '%')">
    <SelectParameters>
        <asp:FormParameter FormField="tSearchBox" Name="Title" Type="String" />
    </SelectParameters>
</asp:SqlDataSource>
<br />
<asp:Label ID="Label1" runat="server" Text="Type ISBN to loan:"></asp:Label>

And here is the .cs file:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;

public partial class Pages_SearchResults : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}
protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
{
    Response.Redirect("Default.aspx");
}


protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
{
    SqlConnection con = new SqlConnection();
    con.ConnectionString = "Data Source=.\\SQLEXPRESS;AttachDbFilename=D:\\Users\\SUUSER\\Documents\\Visual Studio 2010\\Projects\\Library\\LibWebSite\\App_Data\\LibDatabase.mdf;Integrated Security=True;User Instance=True";

    Int32 verify;

    string title = GridView1.HeaderRow.Cells[0].Text, isbn = GridView1.HeaderRow.Cells[1].Text, name = GridView1.HeaderRow.Cells[2].Text, lname = GridView1.HeaderRow.Cells[3].Text, type = GridView1.HeaderRow.Cells[4].Text, year = GridView1.HeaderRow.Cells[5].Text;


}
protected void bLoanButton_Click(object sender, EventArgs e)
{
    SqlConnection con = new SqlConnection();
    con.ConnectionString = "Data Source=.\\SQLEXPRESS;AttachDbFilename=D:\\Users\\SUUSER\\Documents\\Visual Studio 2010\\Projects\\Library\\LibWebSite\\App_Data\\LibDatabase.mdf;Integrated Security=True;User Instance=True";

    string user = "select CurrentID from CurrentUser";

    SqlCommand cmd1 = new SqlCommand(user, con);
    con.Open();
    string get = cmd1.ExecuteScalar().ToString();

    string query1 = "insert into LoanTable(StudId,ISBN,onBorrow) values ("
        + "'" + get + "'" + "," + "'" + tLoanBox.Text + "'" + ","
        + "'" + "1" + "'" + ")";

    string numQuery = "select numOfCopies from Items where ISBN='" + tLoanBox.Text + "'";

    SqlCommand cmdnumQuery = new SqlCommand(numQuery, con);

    SqlCommand cmd2 = new SqlCommand(query1, con);

    int result;

    int num=Convert.ToInt32(cmdnumQuery.ExecuteScalar());


    result = cmd2.ExecuteNonQuery();

    if (num > 0)
    {

        if (result > 0)
            Response.Redirect("LoanSuccesfull.aspx");
    }
    else
        notAvailable.Visible = true;

    con.Close();


}
}

And here is the code for loan button:

 protected void bLoanButton_Click(object sender, EventArgs e)
{
    SqlConnection con = new SqlConnection();
    con.ConnectionString = "Data Source=.\\SQLEXPRESS;AttachDbFilename=D:\\Users\\SUUSER\\Documents\\Visual Studio 2010\\Projects\\Library\\LibWebSite\\App_Data\\LibDatabase.mdf;Integrated Security=True;User Instance=True";

    string user = "select CurrentID from CurrentUser";

    SqlCommand cmd1 = new SqlCommand(user, con);
    con.Open();
    string get = cmd1.ExecuteScalar().ToString();

    string query1 = "insert into LoanTable(StudId,ISBN,onBorrow) values ("
        + "'" + get + "'" + "," + "'" + tLoanBox.Text + "'" + ","
        + "'" + "1" + "'" + ")";





    SqlCommand cmd2 = new SqlCommand(query1, con);

    int result;




    result = cmd2.ExecuteNonQuery();



        if (result > 0)
        {
            loanSuccesful.Visible = true;
            Response.Redirect("LoanSuccesfull.aspx");

        }





    con.Close();


}

I appreciate any help. Thanks

回答1:

All you have to do is In your bLoanButton_Click , add a line to rebind the Grid to the SqlDataSource :

protected void bLoanButton_Click(object sender, EventArgs e)
{

//your same code
........

GridView1.DataBind();


}

regards

回答2:

I was totally lost on why my Gridview.Databind() would not refresh.

My issue, I discovered, was my gridview was inside a UpdatePanel. To get my GridView to FINALLY refresh was this:

gvServerConfiguration.Databind()
uppServerConfiguration.Update()

uppServerConfiguration is the id associated with my UpdatePanel in my asp.net code.

Hope this helps someone.

回答3:

Before data bind change gridview databinding method, assign GridView.EditIndex to -1. It solved the same issue for me :

 gvTypes.EditIndex = -1;
 gvTypes.DataBind();

gvTypes is my GridView ID.

回答4:

Adding the GridView1.DataBind() to the button click event did not work for me. However, adding it to the SqlDataSource1_Updated event did though.

Protected Sub SqlDataSource1_Updated(sender As Object, e As SqlDataSourceStatusEventArgs) Handles SqlDataSource1.Updated
    GridView1.DataBind()
End Sub