Save button click event getting fired up on refreshing the page once done with binding the data to a gridview through save button in asp.net

Question

I am working on a web application using C# and ASP.NET. I am binding the data to the gridview through the textboxes in the same page and I wrote the binding method in my "Save" button click event.

Now, it's really strange thing to find that the grid view is getting bound again with duplicate rows once I refresh the page up on saving the data to the gridview from textboxes through "save" button_click event. I have tried loading the page on firefox, chrome and IE 8....but the result is negative....

Could anyone let me know why is it happening and guide me to resolve it....

This is my C# code:

string con = ConfigurationSettings.AppSettings["ConnectionStrings"];

protected void Page_Load(object sender, EventArgs e) {

    tbladdasset.Visible = false;
    btnsaveasset.Enabled = false;
    lblErrMsg.Text = "";

    if (!IsPostBack)
    {
        bindassets("", "");
        ViewState["sortOrder"] = "";
    }
}

private void bindassets(string sortExp, string sortDir)
{
    try
    {
        SqlConnection con1 = new SqlConnection(con);
        con1.Open();
        SqlCommand cmd = new SqlCommand("select Description,CONVERT(VARCHAR(10), RecievedDate, 101) as DateRecieved,cost,Modelno,Quantity from Asset", con1);
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        da.Fill(dt);
        con1.Close();

        if (dt.Rows.Count > 0)
        {
            DataView dv = dt.DefaultView;

            if (sortExp != string.Empty)
            {
                dv.Sort = string.Format("{0} {1}", sortExp, sortDir);
            }

            grdvAssets.DataSource = dv;
            grdvAssets.DataBind();

        }
        else
        {
            lblErrMsg.Text = "No data found...";
        }

        btnsaveasset.Enabled = false;
        tbladdasset.Visible = false;
    }
    catch
    {
        lblErrMsg.Text = "Failed to connect server...";
    }
}

protected void btnaddnew_Click(object sender, EventArgs e)
{
    tbladdasset.Visible = true;
    btnsaveasset.Enabled = true;
    lblErrMsg.Text = "";
    txtdescription.Text = "";
    txtdtrecieved.Text = "";
    txtcost.Text = "";
    txtmodelno.Text = "";
    txtquantity.Text = "";
}

protected void btnsaveasset_Click(object sender, EventArgs e)
{
        if (txtdescription.Text != "" && txtdtrecieved.Text != "" && txtcost.Text != "" && txtmodelno.Text != "" && txtquantity.Text != "")
        {
            try
            {
                string desc= txtdescription.Text;
                DateTime dtrecd = Convert.ToDateTime(txtdtrecieved.Text);
                string cost = txtcost.Text;
                string modelno = txtmodelno.Text;
                double quantity = Convert.ToDouble(txtquantity.Text);
                SqlConnection sqlcon = new SqlConnection(con);
                sqlcon.Open();
                string save = "Insert into Asset(Description,Recieveddate,cost,Modelno,Quantity)values(@desc,@date,@cost,@modelno,@quantity)";
                SqlCommand cmd = new SqlCommand(save, sqlcon);
                cmd.CommandType = CommandType.Text;
                cmd.Parameters.Add("@desc", desc);
                cmd.Parameters.Add("@date", dtrecd);
                cmd.Parameters.Add("@cost", cost);
                cmd.Parameters.Add("@modelno", modelno);
                cmd.Parameters.Add("@quantity", quantity);
                cmd.ExecuteNonQuery();
                sqlcon.Close();
                bindassets("", "");
                btnsaveasset.Enabled = false;
                txtdescription.Text = "";
                txtdtrecieved.Text = "";
                txtcost.Text = "";
                txtmodelno.Text = "";
                txtquantity.Text = "";
                lblErrMsg.Text = "data inserted successfully..";
            }
            catch
            {
                lblErrMsg.Text = "Please enter valid data and try again...";
            }
        }
        else
        {
            lblErrMsg.Text = "Please enter valid data and try again...";
        }

}

protected void grdvAssets_Sorting(object sender, GridViewSortEventArgs e)
{
    bindassets(e.SortExpression, sortOrder);
}

public string sortOrder
{
    get
    {
        if (ViewState["sortOrder"].ToString() == "desc")
        {
            ViewState["sortOrder"] = "asc";
        }
        else
        {
            ViewState["sortOrder"] = "desc";
        }

        return ViewState["sortOrder"].ToString();
    }
    set
    {
        ViewState["sortOrder"] = value;
    }
}

Anyone please help me.....Thanks in advance..

Solution

that's a common problem. check similar SO questions: Webforms Refresh problem, How to stop unwanted postback.

if a few words, web browser refresh button just sends the last request to the server in your case that's a "Save" button click event, thus it gives duplicate rows. use Response.Redirect, this way the last request will be just navigation to the page, so the refresh will not cause undesired effects.

EDITED

I see you have added some code. here's a workaround for you. the fact that you are saving data to database helps a lot. first thing on page load event no need to check if page IsPostBack, just call the bindassets("", ""); method.

as for save button click event. no need to call the bindassets("", ""); it will be called from page load.

protected void btnsaveasset_Click(object sender, EventArgs e)
{
        if (txtdescription.Text != "" && txtdtrecieved.Text != "" && txtcost.Text != "" && txtmodelno.Text != "" && txtquantity.Text != "")
        {
            try
            {
                string desc= txtdescription.Text;
                DateTime dtrecd = Convert.ToDateTime(txtdtrecieved.Text);
                string cost = txtcost.Text;
                string modelno = txtmodelno.Text;
                double quantity = Convert.ToDouble(txtquantity.Text);
                SqlConnection sqlcon = new SqlConnection(con);
                sqlcon.Open();
                string save = "Insert into Asset(Description,Recieveddate,cost,Modelno,Quantity)values(@desc,@date,@cost,@modelno,@quantity)";
                SqlCommand cmd = new SqlCommand(save, sqlcon);
                cmd.CommandType = CommandType.Text;
                cmd.Parameters.Add("@desc", desc);
                cmd.Parameters.Add("@date", dtrecd);
                cmd.Parameters.Add("@cost", cost);
                cmd.Parameters.Add("@modelno", modelno);
                cmd.Parameters.Add("@quantity", quantity);
                cmd.ExecuteNonQuery();
                sqlcon.Close();
                //bindassets("", "");
                btnsaveasset.Enabled = false;
                txtdescription.Text = "";
                txtdtrecieved.Text = "";
                txtcost.Text = "";
                txtmodelno.Text = "";
                txtquantity.Text = "";
                lblErrMsg.Text = "data inserted successfully..";

            }
            catch
            {
                lblErrMsg.Text = "Please enter valid data and try again...";
            }
        }
        else
        {
            lblErrMsg.Text = "Please enter valid data and try again...";
        }
        Response.Redirect("nameofpage.aspx", false);//does a charm. browser refresh button will repeat last action and from now on that's a Response.Redirect("nameofpage.aspx", false). thus no duplicate records
}