Re: Generics - casting int/double to - C# Discussion Boards

DaveyM6924-Jan-09 22:19

DaveyM69

24-Jan-09 22:19

You may be able to create a generic interface, and provide an implementation for each numric type you wish to support... could be an interesting solution if it works, I haven't tried it.

There's also an excellent article here on CP[^] about generic numerics.

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

S. Senthil Kumar24-Jan-09 22:54

S. Senthil Kumar

24-Jan-09 22:54

You could also use System.Convert.ChangeType[^], like

NextNum = Convert.ChangeType(typeof(T), ..);

Regards
Senthil [MVP - Visual C#]
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devvvy25-Jan-09 14:12

devvvy

25-Jan-09 14:12

Thanks, I have used Convert class since birth of .NET but never seen ChangeType. Good to know!

dev

DaveyM6924-Jan-09 22:57

DaveyM69

24-Jan-09 22:57

The generic interface method does work.

IRand<int> intVersion = new Rand(); ;
Console.WriteLine(intVersion.GetNext(1, 2, new List<int>()));
IRand<long> longVersion = new Rand(); ;
Console.WriteLine(longVersion.GetNext(1, 2, new List<long>()));

public interface IRand<T>
{
    T GetNext(T min, T max, List<T> exclude);
}

public class Rand : IRand<int>, IRand<long>
{
    public int GetNext(int min, int max, List<int> exclude)
    {
        int result = 0;
        // do stuff
        return result;
    }

    #region IRand<long> Members

    public long GetNext(long min, long max, List<long> exclude)
    {
        long result = 0;
        // do stuff
        return result;
    }

    #endregion
}

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

devvvy25-Jan-09 14:10

devvvy

25-Jan-09 14:10

Thanks, I just found it. This is from Darwen[^], which involves declaring <t> as IConvertible.

<br />
class RangedRandom<t><br />
    where T : IConvertible<br />
{<br />
    private Random _random = new Random();<br />
    private double _min;<br />
    private double _range;<br />
    private static readonly Type ElementType = typeof(T);<br />
<br />
    public RangedRandom(T min, T max)<br />
    {<br />
        _min = Convert.ToDouble(min);<br />
        _range = Convert.ToDouble(max) - _min;<br />
    }<br />
<br />
    public T Next()<br />
    {<br />
        double rand = _random.NextDouble();<br />
        double value = _min + (rand * _range);<br />
        return (T)Convert.ChangeType(value, ElementType);<br />
    }<br />
}<br />
</t>

dev

Re: data gridview problem

DaveyM6926-Jan-09 0:15

DaveyM69

26-Jan-09 0:15

Yeah, that could be a good way of achieving what you want. I'd use a try/catch either inside the method or inside the calling method as even if T implements IConvertible, there's no guarantee that the conversion can actually be done - it depends on the class/struct's individual implementation.

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

data gridview problem

bfis10813724-Jan-09 14:01

bfis108137

24-Jan-09 14:01

For whatever reason, when I try to set the value of the DatGridView, it doesn't stick. I have been wrecking by brain over why this is Here is my code

Basically here I am just building the data into my data gridview and then since they will be editing I want the amounts to be loaded into the dgv which is what PopulateList() does.

private void bookList_Load(object sender, EventArgs e)
        {
            BLL = new BooksBLL("C");            
            dataGridView1.DataSource = BLL.allBooks();
            if (isEdit)
            {
                PopulateList();
            }                       
        }

private void PopulateList()
        {
            foreach (OrderedBook ob in order.MyOrderedBooksCollection)
            {
                for (int i = 0; i < dataGridView1.Rows.Count; i++)
                {
                    if (ob.BookCode.ToString() == dataGridView1.Rows[i].Cells[2].Value.ToString())
                        if (ob.CopiesOrdered > 0)
                            dataGridView1.Rows[i].Cells[0].Value = ob.CopiesOrdered.ToString();
                }
            }
        }

Now the interesting thing is that the value property hold and then somehow disappears when the form is loading because when i check the value immediately after a button is pressed without touching anything, it is already null. Note that the dgv works fine other than the fact that the Populate list feature won't load the values.

paas25-Jan-09 6:17

paas

25-Jan-09 6:17

It certainly sounds like your grid's data source is somehow getting reset to its apparent starting value of BLL.allBooks(). Have you considered creating a DataSet, DataTable or DataView from BLL.allBooks and having your PopulateList method update the desired column with 'CopiesOrdered', accepting those changes, and then setting your grid data source to that object?

Can any one help please?

Member 284246824-Jan-09 13:52

Member 2842468

24-Jan-09 13:52

I am doing work in asp.net using c# in VS2008. I would like to give output in java script window because client dont want button and address, tool bars. so i need to design my own window for out put. I am very new in this field. I really don know which ddl i need to use and where i need to place code (in html, in page_load)

Can any one please help me in this regard?

thanks

Not Active24-Jan-09 16:52

Not Active

24-Jan-09 16:52

Member 2842468 wrote:
I am very new in this field.

Then you probably shouldn't have taken on the work. Roll eyes | :rolleyes:

only two letters away from being an asset

Christian Graus25-Jan-09 0:44

Christian Graus

25-Jan-09 0:44

Tell your client you were ripping them off, then buy a book and read it before taking more work. also, when you have ASP.NEt questions, use the ASP.NEt forum.

Christian Graus

Driven to the arms of OSX by Vista.

Guffa25-Jan-09 2:37

25-Jan-09 2:37

Member 2842468 wrote:
I would like to give output in java script window because client dont want button and address, tool bars.

That is not possible. Even if you open a new window using Javascript, you can't get rid of the address field.

Despite everything, the person most likely to be fooling you next is yourself.

NikoTanghe26-Jan-09 3:44

NikoTanghe

26-Jan-09 3:44

yes,

this is possible

from javascript, use:

window.open(url, targetFrame, "toolbar=no,width=500,height=500,resizable,scrollbars");

<< Nearly all men can stand adversity, but if you want to test a man's character, give him power. >>

Guffa26-Jan-09 3:49

26-Jan-09 3:49

No, it's not possible. That doesn't remove the address field.

(It might work it if the page is a file on your own computer, but that's not really relevant.)

Despite everything, the person most likely to be fooling you next is yourself.

Get html from url

macsheriff24-Jan-09 8:00

macsheriff

24-Jan-09 8:00

Hi.
How to get html from url requiring login, with c#? First login the page and then get html.
for instance this url: https://www.google.com/accounts/Login?continue=http://www.google.com/

Guffa24-Jan-09 8:44

24-Jan-09 8:44

Send the login information in a post to the login page and get the cookies that you get in the response. Put the cookies in the request when you get pages that require login.

Despite everything, the person most likely to be fooling you next is yourself.

macsheriff24-Jan-09 9:03

macsheriff

24-Jan-09 9:03

I try this, but is not working. Not login.

CookieContainer cookie = new CookieContainer();
string pageData = string.Empty;
StreamReader respReader = null;

label1.Text = "Finding Site ...";
Application.DoEvents();
HttpWebRequest _mainRequest = (HttpWebRequest)WebRequest.Create("https://www.google.com/accounts/Login?continue=http://www.google.com/");
label1.Text = "Setting Parameters";
Application.DoEvents();
_mainRequest.Method = "POST";
_mainRequest.ContentType = "application/x-www-form-urlencoded";
_mainRequest.CookieContainer = cookie;

label1.Text = "Building String to Send";
Application.DoEvents();
StreamWriter reqWriter = new StreamWriter(_mainRequest.GetRequestStream());
label1.Text = "Sending Form data";
Application.DoEvents();
reqWriter.Write("Email=" + myMail + "&Passwd=" + myPass);
reqWriter.Close();

label1.Text = "Closing Response from Site";
Application.DoEvents();

_mainRequest.GetResponse().Close();

label1.Text = "Looking up secure Site";
Application.DoEvents();
_mainRequest = (HttpWebRequest)WebRequest.Create("http://www.google.com.tr");
_mainRequest.CookieContainer = cookie;
label1.Text = "Getting Response from Site";
Application.DoEvents();
respReader = new StreamReader(_mainRequest.GetResponse().GetResponseStream());
pageData = respReader.ReadToEnd();
label1.Text = "Cleaning up";
Application.DoEvents();
respReader.Close();
label1.Text = "Ready";
textBox1.Text = pageData;
Application.DoEvents();

Guffa24-Jan-09 11:42

24-Jan-09 11:42

You didn't get the cookies from the response.

Despite everything, the person most likely to be fooling you next is yourself.

macsheriff25-Jan-09 4:19

macsheriff

25-Jan-09 4:19

thank you. did work.
I using timer. but, page source code not refresh. Why?

Guffa25-Jan-09 13:57