How to dynamically add and use controls at runtime (use custom - C# Discussion Boards

3-Mar-05 20:42

Can somebody comment this code? ı got this from somewhere but İ couldnt understand why used (-1)?Whats the trick??

<br />
<br />
if (Int32.Parse(myDataSet.Tables[0].Rows[Int32.Parse(((TextBox)myItem.FindControl("textCriteriaNumber")).Text) - 1]["CRITERIA_VALUE"].ToString())==1)<br />
<br />
((CheckBox)myItem.FindControl("cbCriteriaValue1")).Checked = true;<br />
<br />

Re: help me plz

Sebastian Schneider3-Mar-05 22:16

3-Mar-05 22:16

Obviously, the TextBox used for Input contains "normal" counting, e.g. 1 is the first element, 2 is the second element and so on. (1-based)

Arrays in C# have 0 as the first element, 1 as the second etc. (0-based)

So, in order to allow people to enter "1" for the first element, you need to substract 1 in order to get the Index of the corresponding item in the array.

Cheers
Sid

Re: help me plz

Member 17782963-Mar-05 22:36

3-Mar-05 22:36

So many thanks....

Re: help me plz

J4amieC3-Mar-05 22:39

J4amieC

3-Mar-05 22:39

The problem here is that there are many things going on all in one line, making it hard to read if you're not all that C# savvy.

Maybe splitting it up could help you.

// Get a reference to the textbox, a call to FindControl must be cast to the right type
TextBox criteriaNumberTextBox = (TextBox)myItem.FindControl("textCriteriaNumber");
// Get the text value of this textbox and parse it to an int
int criteriaNumber = int.Parse(criteriaNumberTextBox .Text);
//Get the first table in the dataset - remember this is zero based
DataTable firstTable = myDataSet.Tables[0];
// here is the -1 stuff.. im ot sure why the -1 is used but its getting the row BEFORE criteriaNumber above
DataRow rowBeforeCriteriaNumber = firstTable.Rows[criteriaNumber-1];
// get the value of the column named "CRITERIA_VALUE" in the above row. Get it as a string and parse it to an int
int criteriaValue = int.Parse(rowBeforeCriteriaNumber["CRITERIA_VALUE"].ToString());
// if criteriaValue is equal to 1 then find a checkbox control named cbCriteriaValue1 in "myItem" and set it to checked
if(criteriaValue == 1)
{
   CheckBox criteriaValue1 = (CheckBox)myItem.FindControl("cbCriteriaValue1");
   criteriaValue1.Checked = true;
}

* disclaimer - the above was typed quickly, I cant guarantee it is compilable in place of the code you pasted.

Im sorry I cant really help you on why this code uses the -1, it seems a bit weird. This is often used to get the last item in an array - as they are zero based the arraylist.count-1 is the last item in the arraylist. However this doesnt appear to be the case with the above code - unless textCriteriaNumber holds the count of an arraylist.

Anyway, maybe commenting the code helps you understand it better.

Re: question

Member 17782964-Mar-05 1:58

4-Mar-05 1:58

I want to check one of my checkboxes in datagrid..but when i check one of them, i got a javascript error at the bottom of my page...Is there something wrong with my code??Can you see??

<br />
private void adjustQuestionsGrid(int centerId)<br />
		{<br />
			coreMarseg.clinicalTrials mySurvey = new coreMarseg.clinicalTrials();<br />
			DataSet myDataSet = mySurvey.getSurveyDetail(centerId);<br />
<br />
			DataGridItem myItem;<br />
<br />
			for(int i=0;i < myDataGrid.Items.Count; i++)<br />
			{<br />
				myItem = myDataGrid.Items[i];<br />
				if ((myItem.ItemType != ListItemType.Header) &&<br />
					(myItem.ItemType != ListItemType.Footer) &&<br />
					(myItem.ItemType != ListItemType.Separator)) <br />
				{<br />
					((CheckBox)myItem.FindControl("cbQuestionValue0")).Checked = false;<br />
					((CheckBox)myItem.FindControl("cbQuestionValue1")).Checked = false;<br />
					<br />
<br />
					if (Int32.Parse(myDataSet.Tables[0].Rows[Int32.Parse(((TextBox)myItem.FindControl("textQuestionId")).Text) - 1]["SD_QUESTION_VALUE"].ToString())==0)<br />
						((CheckBox)myItem.FindControl("cbQuestionValue0")).Checked = true;<br />
<br />
					if (Int32.Parse(myDataSet.Tables[0].Rows[Int32.Parse(((TextBox)myItem.FindControl("textQuestionId")).Text) - 1]["SD_QUESTION_VALUE"].ToString())==1)<br />
						((CheckBox)myItem.FindControl("cbQuestionValue1")).Checked = true;<br />
<br />
				}<br />
			}<br />
		}<br />
<br />
<br />
<br />
<br />
<br />
<br />
private void myDataGrid_ItemCreated(object sender, System.Web.UI.WebControls.DataGridItemEventArgs e)<br />
		{<br />
			CheckBox myCheckBox;<br />
<br />
			if ((e.Item.ItemType == ListItemType.Item) || (e.Item.ItemType == ListItemType.AlternatingItem))<br />
			{<br />
				myCheckBox = (CheckBox)e.Item.FindControl("cbQuestionValue0");<br />
				myCheckBox.Attributes.Add("OnClick", "adjustQuestionsGridRow(this);");<br />
<br />
				myCheckBox = (CheckBox)e.Item.FindControl("cbQuestionValue1");<br />
				myCheckBox.Attributes.Add("OnClick", "adjustQuestionsGridRow(this);");			<br />
			}<br />
		}<br />
<br />

function adjustQuestionsGridRow(cb) {

cb.parentElement.parentElement.children.item(1).children.item(0).checked = false;
cb.parentElement.parentElement.children.item(2).children.item(0).checked = false;

cb.checked = true;
}

Re:

Member 17782966-Mar-05 18:47

How to dynamically add and use controls at runtime (use custom

6-Mar-05 18:47

Can someone help my question??

oohungoo3-Mar-05 19:56

oohungoo

3-Mar-05 19:56

Assum that I have a form1 with a tab control.
In form1, I have variables, some ArrayList for example.
ArrayList arr1
ArrayList arr2
....
These ArrayList contain names of properties (key) and values of these

properties (int value)
Now I would like to create a template that is a Tab Page which

contains:
- A combo box displays name of elements of selected ArrayList of form1
- A textbox that display value of any element that I selected from the

combo box
Each time I change the value in the textbox, the value in appropriate

ArrayList will change.
Afterall, I can create a new instance and add this template-Tab Page to

the tab control of form1.
In fact, this tag page can be delete whenever I select another array

list (at runtime, I may choose it from a combo box contained in form1)

That all I need to learn. Please help me how to do this.
Thankx

Problem with MDI Child form.

Saurabh Mundhra3-Mar-05 19:44

Saurabh Mundhra

3-Mar-05 19:44

I have an application in which when i open the MDI Child for in maximised state the button controls at the bottom of the form are not visible. They are hidden behind the status bar.

Once i resize the child form and maximize it again i can see the butons.

Can any one help with this kind of a problem

Re: Problem with MDI Child form.

Pushkar Pathak15-Mar-05 20:43

Pushkar Pathak

15-Mar-05 20:43

try aligning the button edges to the borders .... I had that kinda of issue but I got around by trial and error

Pushkar Pathak

Read / Write an Image file

Rob Tomson3-Mar-05 17:20

3-Mar-05 17:20

I'm having problems trying to accomplish a certain task. I want to save some custom information about an image and then save the image itself in the same file. I can write and read my infomation by itself using a binary writer/reader but as soon as I try to throw a System.Drawing.Image in the mix things get messed up. Am I going about using the image correctly like this:

...<br />
System.IO.FileStream iStream = new System.IO.FileStream(FileName, System.IO.FileMode.Append, System.IO.FileAccess.Write);<br />
Image.Save(iStream, System.Drawing.Imaging.ImageFormat.Png);<br />
...

It seems to me that as soon as I do the above code the filestream gets all weird and I it's no longer in a readable format.

Please help,
Rob Tomson

--
There are 10 kinds of people. Those who understand binary and those who don't.

Yulianto.3-Mar-05 19:15

Yulianto.

3-Mar-05 19:15

Rob Tomson wrote:
System.IO.FileStream iStream = new System.IO.FileStream(FileName, System.IO.FileMode.Append, System.IO.FileAccess.Write);

Why do you Append? Try Create or Truncate.

<italic>Work hard and a bit of luck is the key to success.

You don`t need to be genius, to be rich.

Rob Tomson3-Mar-05 19:24

3-Mar-05 19:24

I was doing Append because the code before this writes my custom information that I want before the actual image. If I just do Create then it would overwrite all the info I just wrote. I've also tried just writing my stuff then writing the image through one FileStream but I get the same effect of not being able to read the file afterwards.

Thanks,
Rob Tomson

--
There are 10 kinds of people. Those who understand binary and those who don't.

leppie3-Mar-05 20:36

leppie

3-Mar-05 20:36

You cant do that, it break the file format. Alternatively, it you wanna encapsulate the image files, you can embed them in the Stream, but you will have to setup (preferably another) Stream to supply only the correct offsets for Image.FromStream() to work.

^{xacc-ide 0.0.15 now with C#, MSIL, C, XML, ASP.NET, Nemerle, MyXaml and HLSL coloring - Screenshots}

Rob Tomson3-Mar-05 20:38

3-Mar-05 20:38

How would I go about doing that?

Thanks,
Rob

--
There are 10 kinds of people. Those who understand binary and those who don't.

Sebastian Schneider3-Mar-05 22:24

3-Mar-05 22:24

Well, if I wanted to save an Image along with additional info, I would (as I am using NTFS) use alternate data streams to store my info.

This means, any Image-Processor can still load that file (if the image is in a common format) and my program could utilize the additional data streams attached to the image file.

If you really need to save everything into one stream, try writing an offset first.

This means:

Save into the very first bytes of your file (lets say: the first 4 bytes) an integer which contains the exact location at which the image data begins.
So: you format your information (be sure to have some kind of delimiter or such) and store it into a string.

Get the length of that string, add 4 and save that integer into your file (BINARY format, not as a string).

Then, append your info-string and the image-data.

That way you will be able to jump to the image data directly, without having to parse the info first.

Thats all.

Sid

Rob Tomson3-Mar-05 22:32

3-Mar-05 22:32

That sounds very interesting, thank you. What do you mean by 'use alternate data streams'? Does this mean I can embedd info in the file and still have other programs read the file? That would really helpful if I could do that instead. Any suggestions?

Thanks,
Rob Tomson

--
There are 10 kinds of people. Those who understand binary and those who don't.

Sebastian Schneider3-Mar-05 22:40

3-Mar-05 22:40

Well, try googling for "alternate data stream NTFS" and you should find plenty of information.

Cheers
Sid

Rob Tomson3-Mar-05 23:05

3-Mar-05 23:05

wow, thank you very much. I didn't know something like this existed and it's very interesting. Looks like this is what I'm going to use.

Thanks,
Rob

--
There are 10 kinds of people. Those who understand binary and those who don't.

Sebastian Schneider3-Mar-05 23:08

unable to see webcontrol on browser

3-Mar-05 23:08

Just do not forget that this only works on recent NTFS versions.

And that it is quite easy to break the alternate streams.

I suggest you do some "experiments" by hand first.

Cheers
Sid

chandtec3-Mar-05 16:41

Re: unable to see webcontrol on browser

3-Mar-05 16:41

Hai ,

I placed one webcontrol on form(web based application - c#.net).

i placed BUTTON . After execution iam unable to see my button on browser.

i also chked visible property . its set to true.

i am unable to find the prob .not only button any webctrl iam not able to display.

kindly solve my prob

my html code

<%@ Page language="c#" Codebehind="WebForm1.aspx.cs" AutoEventWireup="false" Inherits="sai.WebForm1" %>

<title>WebForm1

<asp:button id="Button1" style="Z-INDEX: 101; LEFT: 198px; POSITION: absolute; TOP: 124px" runat="server" text="Button">

Yulianto.3-Mar-05 16:51

Yulianto.

3-Mar-05 16:51

Where's the button in your HTML code?

<italic>Work hard and a bit of luck is the key to success.

You don`t need to be genius, to be rich.

Re:again i pasted code kindly see

chandtec3-Mar-05 17:11

its geeting pasted , so i wrote code

3-Mar-05 17:11

<%@ Page language="c#" Codebehind="WebForm1.aspx.cs" AutoEventWireup="false" Inherits="prob.WebForm1" %>

<title>WebForm1

<asp:button id="Button1" style="Z-INDEX: 101; LEFT: 170px; POSITION: absolute; TOP: 128px" runat="server" text="Button">

chandtec3-Mar-05 17:17

i wrote code for button . its not getting displayed on this form

3-Mar-05 17:17

i pasted codewith asp button but here its not displaying.

<asp:button id="Button1" style="Z-INDEX: 101;LEFT:170px;
POSITION: absolute; TOP:128px" runat="server" text="Button">

chandtec3-Mar-05 17:24