PageIndexChanging error - asp.net

Question

I am using Paging in my code and it throws error "The GridView 'GridView1' fired event PageIndexChanging which wasn't handled."
Following is my code (only the relevant part):
<asp:GridView ID="GridView1" runat="server" AllowPaging="true" PageSize="2"
OnPageIndexChanging="SubmitAppraisalGrid_PageIndexChanging">
</asp:GridView>
Code behind:
protected void btnSubmit_Click(object sender, EventArgs e)
{
string constr = ConfigurationManager.ConnectionStrings["DBConnectionString"].ConnectionString;
using (SqlConnection con = new SqlConnection(constr))
{
using (SqlCommand cmd = new SqlCommand(#"select DB_monitor.name,
DB_monitor.priority, DB_alert.creationtime, DB_message.message from DB_alert
INNER JOIN DB_monitor on DB_alert.monitor = DB_monitor.ID
INNER JOIN DB_message on DB_alert.errmess = DB_message.ID
where DB_monitor.application = #strApplication and DB_monitor.instance =
#strInstances and DB_monitor.priority = #Priority and
DB_alert.creationtime between #FromDate and #ToDate and DB_alert.errmess != '1'"))
{
cmd.Parameters.Add("#strApplication", System.Data.SqlDbType.VarChar);// Set SqlDbType based on your DB column Data-Type
cmd.Parameters.Add("#strInstances", System.Data.SqlDbType.VarChar);
cmd.Parameters.Add("#Priority", System.Data.SqlDbType.Int);
cmd.Parameters.Add("#FromDate", System.Data.SqlDbType.DateTime);
cmd.Parameters.Add("#ToDate", System.Data.SqlDbType.DateTime);
cmd.Parameters["#strApplication"].Value = ddlApplication.SelectedValue;
cmd.Parameters["#strInstances"].Value = ddlInstances.SelectedValue;
cmd.Parameters["#Priority"].Value = ddlPriority.SelectedValue;
//2017-04-01 00:00:00.000
cmd.Parameters["#FromDate"].Value = Calendar1.SelectedDate.ToString("yyyy-MM-dd HH:mm:ss.fff");
cmd.Parameters["#ToDate"].Value = Calendar2.SelectedDate.ToString("yyyy-MM-dd HH:mm:ss.fff");
using (SqlDataAdapter sda = new SqlDataAdapter())
{
cmd.Connection = con;
sda.SelectCommand = cmd;
using (DataTable dt = new DataTable())
{
sda.Fill(dt);
GridView1.DataSource = dt;
GridView1.DataBind();
}
}
}
}
}
} // [Edit: sic!]
}

Answer 1

Hi Aarthi, Do some changes in your code :-
protected void btnSubmit_Click(object sender, EventArgs e)
{
BindGridView();
}
protected void SubmitAppraisalGrid_PageIndexChanging(objectsender,GridViewPageEventArgs e)
{
GridView1.PageIndex = e.NewPageIndex;
BindGridView();
}
protected void BindGridView()
{
string constr = ConfigurationManager.ConnectionStrings["DBConnectionString"].ConnectionString;
using (SqlConnection con = new SqlConnection(constr))
{
using (SqlCommand cmd = new SqlCommand(#"select DB_monitor.name,
DB_monitor.priority, DB_alert.creationtime, DB_message.message from DB_alert
INNER JOIN DB_monitor on DB_alert.monitor = DB_monitor.ID
INNER JOIN DB_message on DB_alert.errmess = DB_message.ID
where DB_monitor.application = #strApplication and DB_monitor.instance =
#strInstances and DB_monitor.priority = #Priority and
DB_alert.creationtime between #FromDate and #ToDate and DB_alert.errmess != '1'"))
{
cmd.Parameters.Add("#strApplication", System.Data.SqlDbType.VarChar);// Set SqlDbType based on your DB column Data-Type
cmd.Parameters.Add("#strInstances", System.Data.SqlDbType.VarChar);
cmd.Parameters.Add("#Priority", System.Data.SqlDbType.Int);
cmd.Parameters.Add("#FromDate", System.Data.SqlDbType.DateTime);
cmd.Parameters.Add("#ToDate", System.Data.SqlDbType.DateTime);
cmd.Parameters["#strApplication"].Value = ddlApplication.SelectedValue;
cmd.Parameters["#strInstances"].Value = ddlInstances.SelectedValue;
cmd.Parameters["#Priority"].Value = ddlPriority.SelectedValue;
//2017-04-01 00:00:00.000
cmd.Parameters["#FromDate"].Value = Calendar1.SelectedDate.ToString("yyyy-MM-dd HH:mm:ss.fff");
cmd.Parameters["#ToDate"].Value = Calendar2.SelectedDate.ToString("yyyy-MM-dd HH:mm:ss.fff");
using (SqlDataAdapter sda = new SqlDataAdapter())
{
cmd.Connection = con;
sda.SelectCommand = cmd;
using (DataTable dt = new DataTable())
{
sda.Fill(dt);
GridView1.DataSource = dt;
GridView1.DataBind();
}
}
}
}
}

Answer 2

You have just declared Page index changing event in your aspx as OnPageIndexChanging="SubmitAppraisalGrid_PageIndexChanging" but have not defined same in your code behind
Just define event handler something like below in your code behind page
protected void GridView1_SubmitAppraisalGrid_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
GridView1.PageIndex = e.NewPageIndex;
GridView1.DataSource = getGridData(); //get datasource for your grid in that method
GridView1.DataBind(); //bind the data
}
Find more at GridView.PageIndexChanging Event
And implement your getGridData() method using the code for fetching the data that written in button click and return data table so that will be assigned to Gridview's datasource.
public DataTable getGridData()
{
string constr = ConfigurationManager.ConnectionStrings["DBConnectionString"].ConnectionString;
using (SqlConnection con = new SqlConnection(constr))
{
using (SqlCommand cmd = new SqlCommand(#"select DB_monitor.name,
DB_monitor.priority, DB_alert.creationtime, DB_message.message from DB_alert
INNER JOIN DB_monitor on DB_alert.monitor = DB_monitor.ID
INNER JOIN DB_message on DB_alert.errmess = DB_message.ID
where DB_monitor.application = #strApplication and DB_monitor.instance =
#strInstances and DB_monitor.priority = #Priority and
DB_alert.creationtime between #FromDate and #ToDate and DB_alert.errmess != '1'"))
{
cmd.Parameters.Add("#strApplication", System.Data.SqlDbType.VarChar);// Set SqlDbType based on your DB column Data-Type
cmd.Parameters.Add("#strInstances", System.Data.SqlDbType.VarChar);
cmd.Parameters.Add("#Priority", System.Data.SqlDbType.Int);
cmd.Parameters.Add("#FromDate", System.Data.SqlDbType.DateTime);
cmd.Parameters.Add("#ToDate", System.Data.SqlDbType.DateTime);
cmd.Parameters["#strApplication"].Value = ddlApplication.SelectedValue;
cmd.Parameters["#strInstances"].Value = ddlInstances.SelectedValue;
cmd.Parameters["#Priority"].Value = ddlPriority.SelectedValue;
//2017-04-01 00:00:00.000
cmd.Parameters["#FromDate"].Value = Calendar1.SelectedDate.ToString("yyyy-MM-dd HH:mm:ss.fff");
cmd.Parameters["#ToDate"].Value = Calendar2.SelectedDate.ToString("yyyy-MM-dd HH:mm:ss.fff");
using (SqlDataAdapter sda = new SqlDataAdapter())
{
cmd.Connection = con;
sda.SelectCommand = cmd;
using (DataTable dt = new DataTable())
{
sda.Fill(dt);
}
}
}
return dt;
}