Re: Passing Linq query results to a different function - C# Discussion Boards

Re: Passing Linq query results to a different function

31-Aug-10 3:57

Hi,

I have the following linq code within my app

var results = (from t in query
where t.ProjectID == new Guid(this.Session["ProjectID"].ToString())
orderby t.Number ascending
select new
{
ID = t.ID,
Tag = t.Number,
Description = t.Description,
SubSystems = GeneralHelper.TagSubSystems(t),
Module = t.Area.Module.Name,
Discipline = t.Discipline.Name,
ITRs = GeneralHelper.TagITRsHTML(t)
});

I want to pass the query result to another function to handle my paging. I currently have another function defined like this

public void BindGridData(IQueryable result)
{
gridView.DataSource = result;
gridView.DataBind();
}

It works like this, but the problem is I cannot do "take" or "skip" on "result" because it's declared as IQueryable. Is there a work around to handle this?

Thanks

brunoseixas31-Aug-10 4:28

brunoseixas

31-Aug-10 4:28

convert the linq result to list

var results = (from t in query
where t.ProjectID == new Guid(this.Session["ProjectID"].ToString())
orderby t.Number ascending
select new
{
ID = t.ID,
Tag = t.Number,
Description = t.Description,
SubSystems = GeneralHelper.TagSubSystems(t),
Module = t.Area.Module.Name,
Discipline = t.Discipline.Name,
ITRs = GeneralHelper.TagITRsHTML(t)
}).ToList();

Re: Passing Linq query results to a different function

Swiftain31-Aug-10 4:41

Re: Passing Linq query results to a different function

31-Aug-10 4:41

If I convert it to list, then how do I define the function that takes the query result?

Not Active31-Aug-10 4:44

Re: Passing Linq query results to a different function

31-Aug-10 4:44

public void BindGridData(IEnumerable result)
{
gridView.DataSource = result;
gridView.DataBind();
}

Also note the use of the pre tags to properly format the code snippet

I know the language. I've read a book. - _Madmatt

Swiftain31-Aug-10 4:48

Re: Passing Linq query results to a different function

31-Aug-10 4:48

IEnumerable requires an argument,

IEnumerable result

any idea what argument would work?

Ian Shlasko31-Aug-10 5:26

Ian Shlasko

31-Aug-10 5:26

Create a structure to represent your query results, instead of using anonymous types. Then you know what kind of IEnumerable it is.

Alternatively, make your Bind function generic, like so:

public void BindGridData<T>(IEnumerable<T> result)
{
  gridView.DataSource = result;
  gridView.DataBind();
}

Proud to have finally moved to the A-Ark. Which one are you in?
Author of the Guardians Saga (Sci-Fi/Fantasy novels)

Re: Passing Linq query results to a different function

Swiftain31-Aug-10 5:42

Re: Passing Linq query results to a different function

31-Aug-10 5:42

That worked! Thanks.

Not Active31-Aug-10 5:50

Re: Passing Linq query results to a different function

31-Aug-10 5:50

Although I agree a concrete type is better for readability and good design it isn't necessary in order to pass the query to a method.

I know the language. I've read a book. - _Madmatt

Swiftain31-Aug-10 5:54

Re: Passing Linq query results to a different function

31-Aug-10 5:54

the reason i didnt define a concrete type is because the function will be accepting queries from different classes

Ian Shlasko31-Aug-10 6:17

Ian Shlasko

31-Aug-10 6:17

Ok, then the second solution is best Smile | :)

Oh, and you don't need to do a ToList() if you're going that route. Linq results are all IEnumerable.

Proud to have finally moved to the A-Ark. Which one are you in?
Author of the Guardians Saga (Sci-Fi/Fantasy novels)

Re: Passing Linq query results to a different function

Not Active31-Aug-10 6:17

Re: Passing Linq query results to a different function

31-Aug-10 6:17

Using generics, as Ian has suggested, doesn't preclude you from doing that. You would just need to create the class/struct for each query, which from a architectural perspective isn't a bad idea. However, if you have many different queries that are possible then perhaps you need to improve your design, one size fits all implementation are very difficult to maintain.

I know the language. I've read a book. - _Madmatt

Swiftain31-Aug-10 22:04

Re: Passing Linq query results to a different function

31-Aug-10 22:04

One more thing,

lets say I store "result" in session variable like this

public void BindGridData<t>(IEnumerable<t> result)
{
Session["result"] = result;
gridView.DataSource = result;
gridView.DataBind();
}

and then I want to call this function within another event, how do I call it? how do I cast Session["result"]?

Thanks

Not Active1-Sep-10 1:41

Re: Passing Linq query results to a different function [modified]

1-Sep-10 1:41

First of all don't store it in session state. Remember this is the result of your query, not the query itself, and could be very large.

It's also quite clear how to cast it. It is being passed into your method as an IEnumerable, guess what it should be cast as?

I know the language. I've read a book. - _Madmatt

Not Active31-Aug-10 5:46

Re: Passing Linq query results to a different function

31-Aug-10 5:46

IEnumerable<T> requires a type but IEnumerable does not.

I know the language. I've read a book. - _Madmatt

modified on Tuesday, August 31, 2010 12:12 PM

Swiftain31-Aug-10 5:55

Re: Passing Linq query results to a different function

31-Aug-10 5:55

???

Not Active31-Aug-10 6:13

Problem with ToolStrip and ToolStripButtons

31-Aug-10 6:13

Sorry, the brackets didn't render. Fix it

I know the language. I've read a book. - _Madmatt

Dewald31-Aug-10 2:50

Dewald

31-Aug-10 2:50

Hi all, I'm hoping someone could shed some light here please.

I have a ToolStripPanel on my form with a few ToolStrips which in turn each have a few ToolStripButtons.

I wrote an event handler for the MouseEnter and MouseLeave events of all of these buttons so that I can change the image depending on whether the mouse is over the button or not. Basically, I have an animated gif which I'm showing when the mouse is over the button and a static image when it's not.

It works but it has a little glitch. Every time the image of a button changes, the size of the button changes very briefly. This means that, for a split second, the relevant ToolStrip is resized which has the effect of all the ToolStrips to the right of it being moved left. Like I say, it's only for a split second before everything is restored again (once the button has its new image) but it makes for a very unpleasant visual effect.

Any ideas?

phil.o31-Aug-10 2:56

phil.o

31-Aug-10 2:56

Hi,

Could you post the code you're using to change the images on your buttons ? This way we would have a better idea on how you handle the stuff.

Dewald31-Aug-10 3:11

Dewald

31-Aug-10 3:11

Sure, I have two functions:

private void toolStripButton_MouseEnter(object sender, EventArgs e)
        {
            switch ((sender as ToolStripItem).Name)
            {
                case "toolStripButton_ViewUser": (sender as ToolStripButton).Image = Properties.Resources.BtnIcon_anim_User; break;
                case "toolStripButton_NewUser": (sender as ToolStripButton).Image = Properties.Resources.BtnIcon_anim_UserAdd; break;
                case "toolStripButton_ViewItems": (sender as ToolStripButton).Image = Properties.Resources.BtnIcon_anim_Item; break;
                case "toolStripButton_NewItems": (sender as ToolStripButton).Image = Properties.Resources.BtnIcon_anim_ItemAdd; break;
                ... etc.
            }
        }

private void toolStripButton_MouseLeave(object sender, EventArgs e)
        {
            switch ((sender as ToolStripItem).Name)
            {
                case "toolStripButton_ViewUser": (sender as ToolStripButton).Image = Properties.Resources.BtnIcon_User; break;
                case "toolStripButton_NewUser": (sender as ToolStripButton).Image = Properties.Resources.BtnIcon_UserAdd; break;
                case "toolStripButton_ViewItems": (sender as ToolStripButton).Image = Properties.Resources.BtnIcon_Item; break;
                case "toolStripButton_NewItems": (sender as ToolStripButton).Image = Properties.Resources.BtnIcon_ItemAdd; break;
                ... etc.
            }
        }

The MouseEnter and MouseLeave events of all the buttons are handled by these two functions.

phil.o31-Aug-10 3:37

phil.o

31-Aug-10 3:37

You can try to encapsulate switch statements between this.SuspendLayout() and this.ResumeLayout(), in order to stop rendering your form while you're changing your images.

You can also try to set the ImageScaling property of your ToolStripButtons to None ; but only if all your images have the same size, and you have set the ImageScalingSize property of your ToolStrip to the actual size of your images.

I don't have VS installed on this machine, so I was not able to test for these solutions. I hope it will help you anyway.

Dewald31-Aug-10 4:35

Dewald

31-Aug-10 4:35

Thanks a mil. I had considered the ImageScaling option but that wouldn't work because the images are in fact bigger than the buttons and have to be scaled. The SuspendLayout() and ResumeLayout() suggestion worked like a charm though, thanks for that.