Telerik's RADGrid, basing on their example on http://demos.telerik.com/aspnet-ajax/grid/examples/dataediting/programaticlinqupdates/defaultcs.aspx
Problem: I can insert and delete, however updating doesn't work. No error trapped. Data just doesn't change.
From the code below it looks like Telerik Grid is doing some kung-fu behind the scenes to wire things up. I can't see the db receiving any update statements.
Question: anything obvious I'm missing?
protected void RadGrid1_UpdateCommand(object source, GridCommandEventArgs e)
{
var editableItem = ((GridEditableItem) e.Item);
var raceId = (Guid) editableItem.GetDataKeyValue("RaceID");
//retrive entity form the Db
var race = DbContext.races.Where(n => n.raceid == raceId).FirstOrDefault();
if (race != null)
{
//update entity's state
editableItem.UpdateValues(race);
try
{
//submit chanages to Db
DbContext.SubmitChanges();
}
catch (Exception f)
{
ShowErrorMessage(f);
}
}
}
Think I may have to go back to their example.. get their db.. and attack from that point of view.
Cheers!
Do a Rebind after your update. Trying adding
RadGrid1.DataSource = null;
RadGrid1.Rebind();
After your call to DbContext.SubmitChanges(); call, assuming you have implemented _NeedDataSource().
Related
I'm trying to get some data from a database whose results can be more than one row.
I've the following code for that:
public System.Linq.IQueryable<Users> getUser2(string idUser)
{
try
{
using (Entities c = new Entities())
{
c.ContextOptions.LazyLoadingEnabled = false;
c.ContextOptions.ProxyCreationEnabled = false;
return c.Users.Include("Empresas").Where(x => x.Login == idUser && x.Empresas.Activa == true);
}
}
catch (Exception ex)
{
throw ex;
}
}
But it doesn't seem to get any result, it shows something like a badly formed Iqueryable, I mean if I expand its results view I can see a message that says "ObjectContext instance has been eliminated and cannot be used for operations that need a connection" If I try to access any Users element with the function ElementAt(index) I get an IndexOutOfBounds error as it looks like it has no data if watched on debug mode.
I've deduced that it's Where fault because this code Works fine in returning the first user it finds that fulfills the condition:
public Users getUser(string idUser)
{
try
{
using (Entities c = new Entities())
{
c.ContextOptions.LazyLoadingEnabled = false;
c.ContextOptions.ProxyCreationEnabled = false;
return c.Users.Include("Empresas").FirstOrDefault(x => x.Login == idUser && x.Empresas.Activa == true);
}
}
catch (Exception ex)
{
throw ex;
}
}
Does that Where work differently than what I think I should? If then, how could I get several data that fulfills the conditions I'm passing the same as in getUser but for several rows?
Thanks for your attention.
You need to enumerate the result, so after the "where" statement add. ToList() which will enumerate and execute the query against your database. FirstOrDefault is executing the query thats why you get a result.
You need to check the deferred methods and understand how they work.
EDIT
The following are some links to show you the deference between the Deferred method vs Immediate methods in LINQ
1- http://www.dotnetcurry.com/showarticle.aspx?ID=750
2- http://www.codeproject.com/Articles/627081/LINQ-Deferred-Execution-Lazy-Evaluation
3- http://visualcsharptutorials.com/linq/deferred-execution
Hope that helps.
I'm adding several rows to a DataTable in my strongly-typed DataSet and use a TableAdapterManager to insert the changes into my database. Using the UpdateAll function of the TableAdapterManager results in case of a failure in a database rollback of all inserted rows. Unfortunately DataTable.RejectChanges does not "rollback" the same rows in the DataTable.
In the call to DataTable.RejectChanges method only the last row is removed from the DataTable. I want the DataSet to have the same status as the database.
Isn't RejectChanges per MSDN documentation deleting all new (uncomitted) rows? Am I doing something wrong?
My code:
foreach (var item in List)
{
DataSet.customerRow custRow = ds.customer.NewcustomerRow();
custRow.name = item.Name;
try
{
ds.customer.AddcustomerRow(custRow);
}
catch (Exception ex)
{
ProcessException(ex, System.Reflection.MethodBase.GetCurrentMethod().Name);
valid=false;
}
}
if (valid)
{
DataSetTableAdapters.TableAdapterManager adapterManager = new DataSetTableAdapters.TableAdapterManager();
adapterManager.customerTableAdapter = new DataSetTableAdapters.customerTableAdapter();
try
{
retryPolicy.ExecuteAction(() =>
{
adapterManager.UpdateAll(ds);
});
}
catch (Exception ex)
{
ds.customer.RejectChanges();
}
}
else
{
ds.customer.RejectChanges();
}
The solution is to set adapterManager.BackupDataSetBeforeUpdate = true; This creates an internal backup copy of the dataset which is "reused" in case of failures.
MSDN: Hierarchical Update Overview
"The backup copy is only in memory during the execution of the TableAdapterManager.UpdateAll method. Therefore, there is no programmatic access to this backup dataset because it either replaces the original dataset or goes out of scope as soon as the TableAdapterManager.UpdateAll method has finished running."
<dx:ASPxGridView ID="ASPxGridView1" runat="server" AutoGenerateColumns="False"
KeyFieldName="CategoryID">
<SettingsEditing Mode="Inline" />
<Columns>
<dx:GridViewCommandColumn VisibleIndex="0">
<EditButton Visible="True"></EditButton>
<NewButton Visible="True"></NewButton>
<DeleteButton Visible="True"></DeleteButton>
</dx:GridViewCommandColumn>
<dx:GridViewDataTextColumn Caption="CategoryID" FieldName="CategoryID"
VisibleIndex="1">
</dx:GridViewDataTextColumn>
<dx:GridViewDataTextColumn Caption="CategoryName" FieldName="CategoryName"
VisibleIndex="2">
</dx:GridViewDataTextColumn>
<dx:GridViewDataTextColumn Caption="Description" FieldName="Description"
VisibleIndex="3">
</dx:GridViewDataTextColumn>
</Columns>
</dx:ASPxGridView>
C# syntax:
NorthwindDataContext db = new NorthwindDataContext();
var lresult = (db.Categories
.Select(p => new { p.CategoryID, p.CategoryName, p.Description}));
ASPxGridView1.DataSource = lresult;
ASPxGridView1.DataBind();
If you run the code, you get a gridview which is filled by NorthWind Categories table. If you click on command button of grid whose are on left side, you get insert/update field, but you have not access to give input. They are gone to read only mode.
If I replace the above C# syntax with below
NorthwindDataContext db = new NorthwindDataContext();
var lresult = (db.Categories);
ASPxGridView1.DataSource = lresult;
ASPxGridView1.DataBind();
then it works fine. Now you can work with command button with out facing any problem.
I want to know what the problem is, why the first syntax does not work. Maybe you say
Anonymous types are class types that consist of one or more public read-only properties. But when you need to join more than one table and need to select several fields not all than what you do. Hope you not say linq is fail to do that or Don't think it is possible. Hope there must be any technique or else something to bind control with Anonymous type. Plz show some syntax .
The problem is that the result set is collection of Anonymous type as you supposed and the grid doesn't know how to treat it. What you have to do is to use RowInserting and RowUpdating events of the grid.
Here is an example of how I use DevExpress grid with NHibernate:
protected void gridAgentGroups_RowInserting(object sender, DevExpress.Web.Data.ASPxDataInsertingEventArgs e)
{
ASPxGridView currentGrid = sender as ASPxGridView;
var currentAgentGroup = new AgentGroup();
if (e.NewValues.Contains("Name"))
{
var newValue = (string)e.NewValues["Name"];
currentAgentGroup.Name = newValue;
}
if (e.NewValues.Contains("PhysicalAddress"))
{
var newValue = (string)e.NewValues["PhysicalAddress"];
currentAgentGroup.PhysicalAddress = newValue;
}
AgentGroupsDataAccess.SaveAgentGroup(currentAgentGroup);
e.Cancel = true;
currentGrid.CancelEdit();
currentGrid.DataBind();
}
protected void gridAgentGroups_RowUpdating(object sender, DevExpress.Web.Data.ASPxDataUpdatingEventArgs e)
{
ASPxGridView currentGrid = sender as ASPxGridView;
int currentAgentGroupId = (int)((AgentGroup)currentGrid.GetRow(currentGrid.EditingRowVisibleIndex)).Id;
var currentAgentGroup = AgentGroups.Where(ag => ag.Id == currentAgentGroupId).FirstOrDefault();
if (e.NewValues.Contains("Name"))
{
var newValue = (string)e.NewValues["Name"];
currentAgentGroup.Name = newValue;
}
if (e.NewValues.Contains("PhysicalAddress"))
{
var newValue = (string)e.NewValues["PhysicalAddress"];
currentAgentGroup.PhysicalAddress = newValue;
}
AgentGroupsDataAccess.SaveAgentGroup(currentAgentGroup);
e.Cancel = true;
currentGrid.CancelEdit();
currentGrid.DataBind();
}
I hope this will help.
Just a wild guess - you're binding your data to the grid using field names - yet, your anonymous type doesn't really have any field names.
Does it make any difference if you try this code:
NorthwindDataContext db = new NorthwindDataContext();
var lresult = (db.Categories
.Select(p => new { CategoryID = p.CategoryID,
CategoryName = p.CategoryName,
Description = p.Description}));
ASPxGridView1.DataSource = lresult;
ASPxGridView1.DataBind();
Again - I don't have the means to test this right now, it's just a gut feeling..... try it - does that help at all??
You actually can bind with anonymous type as you see the already filled rows. But: the grid itself cannot know how you build the query and what to add additionally to the visible columns (if there are valid default values).
As you use Developer Express' grid you have the option to provide your own update / edit form and handle everything needed on your own.
well the problem is that i am trying to get DDL to:
1. Recive catagories from a DB tabel - working
2. OnChange select from a different table the products by the item in the DDL - working
had a problem with No1 but fixed that problem. i found out that to get No1 working i have to use postback. did that and every thing in that part is working well and actualy every thing is working...but my hug problem (and i cant find any good answer for it) is that every time i change the item i a getting all the times all over again(i have initialy 8 item - secont time 16 - 24 etc....)
tried to use: ddlCatagories.Items.Clear();
when i use that i am not getting any duplicates but then, i am not getting any thing, it takes the first catagory from the list every time, no matter what i chose in the list..
trying to figure it out for the past week...please help :-)
public partial class selectNamesFromCatagories : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
ddlCatagories.Items.Clear();
SqlDataReader dr = DbHelper.ExecuteReader(
sqlConn1.home,
"spSelectNamesFromCatagories");
while (dr.Read())
{
ListItem li = new ListItem(dr["CategoryName"].ToString());
ddlCatagories.Items.Add(li);
}
dr.Close();
}
protected void ddlCatagories_SelectedIndexChanged(object sender, EventArgs e)
{
SqlDataReader dr = DbHelper.ExecuteReader(
sqlConn1.home,
"spProductsByCatagoryID",
new SqlParameter("#catName", ddlCatagories.Text)
);
while (dr.Read())
{
TableRow tr = new TableRow();
for (int i = 0; i < dr.FieldCount; i++)
{
TableCell td = new TableCell();
td.Text = dr[i].ToString();
tr.Controls.Add(td);
}
tblProductsByCatagories.Controls.Add(tr);
}
}
}
Only populate the DropDownList on first load by checking whether the page has not posted back ie.
if (!Page.IsPostBack)
{
// Populate list
}
I agree with Dan and would add the following as well if you have any ajax enabled controls as they may generate callbacks.
if (!Page.IsPostBack && !Page.IsCallBack)
{
// Populate list
}
I have a couple of tables with similar relationship structure to the standard Order, OrderLine tables.
When creating a data context, it gives the Order class an OrderLines property that should be populated with OrderLine objects for that particular Order object.
Sure, by default it will delay load the stuff in the OrderLine property but that should be fairly transparent right?
Ok, here is the problem I have: I'm getting an empty list when I go MyOrder.OrderLines but when I go myDataContext.OrderLines.Where(line => line.OrderId == 1) I get the right list.
public void B()
{
var dbContext = new Adis.CA.Repository.Database.CaDataContext(
"<connectionString>");
dbContext.Connection.Open();
dbContext.Transaction = dbContext.Connection.BeginTransaction();
try
{
//!!!Edit: Imortant to note that the order with orderID=1 already exists
//!!!in the database
//just add some new order lines to make sure there are some
var NewOrderLines = new List<OrderLines>()
{
new OrderLine() { OrderID=1, LineID=300 },
new OrderLine() { OrderID=1, LineID=301 },
new OrderLine() { OrderID=1, LineID=302 },
new OrderLine() { OrderID=1, LineID=303 }
};
dbContext.OrderLines.InsertAllOnSubmit(NewOrderLines);
dbContext.SubmitChanges();
//this will give me the 4 rows I just inserted
var orderLinesDirect = dbContext.OrderLines
.Where(orderLine => orderLine.OrderID == 1);
var order = dbContext.Orders.Where(order => order.OrderID == 1);
//this will be an empty list
var orderLinesThroughOrder = order.OrderLines;
}
catch (System.Data.SqlClient.SqlException e)
{
dbContext.Transaction.Rollback();
throw;
}
finally
{
dbContext.Transaction.Rollback();
dbContext.Dispose();
dbContext = null;
}
}
So as far as I can see, I'm not doing anything particularly strange but I would think that orderLinesDirect and orderLinesThroughOrder would give me the same result set.
Can anyone tell me why it doesn't?
You're just adding OrderLines; not any actual Orders. So the Where on dbContext.Orders returns an empty list.
How you can still find the property OrderLines on order I don't understand, so I may be goofing up here.
[Edit]
Could you update the example to show actual types, especially of the order variable? Imo, it shoud be an IQueryable<Order>, but it's strange that you can .OrderLines into that. Try adding a First() or FirstOrDefault() after the Where.