Getting query strings (array)

Toh Zuan Yi

15y3.1k.NET

hi.. i have a question here i need help with. its almost the same as my post earlier, but no one replied to that post :( thats ok i have a simpler question here... i was asking how to request multiple querystrings, but it was actually one querystring("ID") but that "ID" contained more than 1 value. Example, i have a PDF.aspx page(page that converts to PDF) and Print.aspx page. On the Print.aspx, i get the values and store it in array(am i doing it correct?)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Collections;

protected void btnPrint_Click(object sender, EventArgs e)
{
ArrayList ID = new ArrayList(); //Declare new ArrayList

DateTime selectedDate1; //Set to DateTime
DateTime selectedDate2; //Set to DateTime

int userID = UserManager.GetUserID(HttpContext.Current.User.Identity.Name); //GetUserID

selectedDate1 = DateTime.Parse(this.txtDate1.Text.Trim()); //assign selectedDate value = textbox value
selectedDate2 = DateTime.Parse(this.txtDate2.Text.Trim()); //assign selectedDate value = textbox value

ID.Add(DataManager.GetMedicationListByDate(userID, selectedDate1, selectedDate2)); //add value into array

Response.Redirect("PDF.aspx?ID=" + ID); // transfer to a new page
}

ok now i want to transfer the values to the PDF. page which need to get the values and display on each page in PDF. I need to get the querystring which i set as an array but i dont pretty know how to do it so i did some research but still not sure zzzzzz. My code goes like this

using System;
using System.IO;
using System.Collections;
using System.Linq;
using TallComponents.PDF.Layout;
using TallComponents.PDF.Layout.Paragraphs;
using TallComponents.PDF.Layout.Brushes;
using TallComponents.PDF.Layout.Fonts;

protected void Page_Load(object sender, EventArgs e)
{

// create document
Document doc = new Document();

// add a section
Section section = doc.Sections.Add();
section.PageSize = PageSize.A4;

int medicationListID = int.Parse(Request.QueryString["ID"]); // error here "Input string was not in a correct format."

if (int.Parse(Request.QueryString["ID"]) != null)
{
int[] selectedIDs = ID.Cast().ToArray(); //Is this Correct?

foreach (int intValue in selectedIDs)
{
//get the data of the medication according to ID
MedicationList medicationList = DataManager.SelectMedicationList(medicationListID);

//start on a new page
section.StartOnNewPage = true;

//Does all my actions displaying

}//end of foreach statement
}//end of IF statement
// save the PDF directly to the browser
doc.Write(Response);
}//end of pageload

can anyone help me with this? i need to make it working asap.

6 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes15y ago
Accepted answer
Well, I'd have said that the URL you're redirecting to is going to end up as:

PDF.aspx?ID=System.Collections.ArrayList

This is because the ID.ToString() method just gives the name of the type, so there's no way that you're going to be able to recover the individual values from that.

If you only want to use one query string, then you'll need to figure out a way to concatenate the values together. Suppose, for example, you use the underscore as a separator:

string query = "";
for(int i = 0; i < ID.Count; i++)
{
query += ID[i].ToString();
if (i < ID.Count - 1) query += "_";
}

Response.Redirect("PDF.aspx?ID=" + query); // transfer to a new page

You could then recover the individual values as follows:

string combined = Request.QueryString["ID"];
string[] items = combined.Split('_');
int[] selectedIDs = new int[items.Length];
for(int i = 0; i < items.Length; i++) selectedIds[i] = int.Parse(items[i]);
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Sam Hobbs15y ago
Note that in the sample that Vulpes provided, he chose to use "_" (underscore) as the delimiter. You did not specify to use an underscore but that is what he used. I was simply asking what you were using. I assume that you were not using a delimiter, but eventhough you did not know that you needed a delimiter, you did.

Also note that Vulpes is using String.Split, which is what I was also suggesting. For dong the reverse, the concatenation, the following uses String.Join.

string[] sa = new string[ID.Count];
for (int i = 0; i < ID.Count; i++)
sa[i] = ID[i].ToString();
Response.Redirect("PDF.aspx?ID=" + string.Join("_", sa)); // transfer to a new page
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Toh Zuan Yi15y ago
you are right mr.hobbs, but im going to be passing a whole array of IDs over, and that array is going to contain the 1 And 2 And 3 or 1 Or 2 Or 3 or just 2 And 3 or 2 Or 3. Ive got it working now, thank you for all your replies.
0
Sam Hobbs15y ago
How does your program know that it is "1 and 2 and 3 or just 1 and 3 or just 2 and 3 or just 1 Or 2 Or 3"? Is there always just one digit so that the corresponding value of ID would be 123 or just 13 or just 23 or just 1 or 2 or 3? If not, then you are using a delimiter to separate each number. If ID is "1 and 2 and 3" then what would that actually look like in the URL (the part after "PDF.aspx?")? I think you misunderstand what I mean when I say delimiter. Unless 1 and 2 and 3 is put into the query string as "123" then you are using a delimiter.
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Toh Zuan Yi15y ago
hi both, im grateful for your replies. Mr.Hobbs, i am not using any delimiters because i have only one quesrystring thats just "ID" and it can vary for example the ID might be 1 and 2 and 3 or just 1 and 3 or just 2 and 3 or just 1 Or 2 Or 3.

Mr.Vulpes, i have a question to ask for your solution. a simple one though, is the

for(int i = 0; i < items.Length; i++) selectedIds[i] = int.Parse(items[i]);

does this mean that int.parse(items[i]) is each of the selected IDs? example if the querystring received 3 IDs(1, 2 and 3), this sentence would be to seperate them to each ID? if so, how can i put that int.parse(items[i]) to use? can i do it like this?

int medicationID = int.Parse(items[i]);

and then using my datamanager to get the data according to their ID

MedicationList medicationList = DataManager.SelectMedicationList(medicationID);

appreciate your replies
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Sam Hobbs15y ago
I am not as experienced with ASP as many others, but I am familair with the use of strings in .Net. I think you just need to use String.Join to create the query string and String.Split to convert it back to an array. I am not sure however what you should use as the delimter. I assume that you do not want to use "&" but you can choose some other delimiter that your program uses just for that purpose.
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