In my program i'm currently working on programmatically adding a variety of form objects in C#. For example i'm trying to create a certain group of panels, which contain the data I wish to show. When loading the form I have a file which contains all of the data I wish to load in, the loading itself works fine but when loading I need to create a variety of form labels, panels and images to display all of the necessary data and as such I need to make these panels and labels all with a seperate name, but programmatically.
for (int i=0; i<fileLength; i++)
{
Panel pnl = New Panel();
pnl.Name = "pnl1"+i;
//Set the other properties here
}
What i'm trying to do if use an iterator to append the current iteration to the end of the name. Am I going the right way about it? Or should I be doing a different method?
You cannot change variable/object name at runtime. If you want to write code against the object than you need to keep a reference to it. In your case you have changed the Name property of Panel but still you have to use it as pnl, not as pnl0 or pnl1.
The other way for doing this would be to use a Dictionary with key as the name as you assign and value as the object itself. This will help you in accessing your controls using its name that you have assigned to it.
Dictionary<string, Panel> panels = new Dictionary<string, Panel>();
for (i = 0; i <= 10; i++) {
Panel pnl = new Panel();
panels.Add("pnl" + i.ToString(), pnl);
}
//write code against panels
panels("pnl0").Width = 100;
For accessing within loop:
foreach (string pnlName in panels.Keys) {
panels(pnlName).Visible = true;
}
for (i = 0; i <= 10; i++) {
panels("pnl" + i).Visible = true;
}
Related
I'm working on an inventory program and have finished the main functionality as a command line console app. I am now working on a version for winforms. I want to enable it to dynamically generate a Groupbox that holds some textboxes. I'd rather not design 50+ lines of multiple textboxes. Keep in mind I'm rather new to programming, having started with C# a year ago. I know next to nothing on Winforms.
I've tried to use dynamic item = new Groupbox();as a similar method allowed generation of objects at runtime. In the command line app, the way it works is that based on information given, a certain amount of objects are passed into the list _AllItems. I was thinking of generating the Groupboxes by using:
private void InitializeGroupBox()
{
foreach (Product product in Product._AllItems)
{
dynamic Item = new GroupBox();
}
}
But I have the feeling I'm nowhere near the correct method. Thanks to anybody who helps.
You will need to learn a bit more, but here is what I usually do to achieve what you asked.
internal class DynamicForm : Form
{
private FlowLayoutPanel mFlowLayoutPanel;
public DynamicForm()
{
mFlowLayoutPanel = new FlowLayoutPanel();
mFlowLayoutPanel.Dock = DockStyle.Fill;
// Add to this Form
this.Controls.Add(mFlowLayoutPanel);
InitializeGroupBox();
}
private void InitializeGroupBox()
{
mFlowLayoutPanel.SuspendLayout(); // Performance
for (int i = 1; i <= 20; i++) {
var groupBox = new GroupBox();
groupBox.Text = "GroupBox #" + i;
groupBox.Size = new Size(200, 50);
var textBox = new TextBox();
textBox.Dock = DockStyle.Fill;
// Add the TextBox to GroupBox
groupBox.Controls.Add(textBox);
// Add to this Form
mFlowLayoutPanel.Controls.Add(groupBox);
}
mFlowLayoutPanel.ResumeLayout(); // after suspend, resume!
}
}
I have created a panel in my page view (tour.aspx file).
Now I want to access it in my class file (add_tour.cs file).
This is my panel:
<asp:Panel ID="itinerary_panel" runat="server"></asp:Panel>
This is my code behind tour.aspx file:
add_tour tour_obj = new add_tour();
int days_count = 2;
tour_obj.textbox_generator(days_count);
And this code is in add_tour.cs file:
public void textbox_generator(int days_count)
{
}
Now how to access the panel from aspx file?
Please help.
There's no need to actually add the text boxes to the panel from this class.
public List<TextBox> textbox_generator(int days_count)
{
var textBoxes = new List<TextBox>();
for(int i = 0; i < days_count; i++)
{
txt_desc = new TextBox();
txt_desc.ID = "txt_desc" + i.ToString();
txt_desc.CssClass = "form-control";
txt_desc.Attributes.Add("placeholder", "Enter day " + i + " description");
txt_desc.TextMode = TextBoxMode.MultiLine;
textBoxes.Add(txt_desc);
}
return textBoxes;
}
Then change your code behind to:
add_tour tour_obj = new add_tour();
int days_count = 2;
var textBoxes = tour_obj.textbox_generator(days_count);
foreach(var textBox in textBoxes)
{
itinerary_panel.Controls.Add(textBox);
}
Note that you need to be careful where you add these controls in the page lifecycle. See Microsoft documentation.
This keeps your textbox_generator from needing to know anything about the specific page using it.
Also, you should really align your naming conventions with C# standards. Use PascalCasing. textbox_generator should be TextBoxGenerator etc. And you can probably make textbox_generator into a static method if it doesn't need to access any fields or properties of its class.
If you really wanted your other class to itself add the controls directly to the panel, then you would just pass a reference to the panel from the code behind to the class.
public void textbox_generator(int days_count, Panel panel)
{
for(int i = 0; i < days_count; i++)
{
txt_desc = new TextBox();
txt_desc.ID = "txt_desc" + i.ToString();
txt_desc.CssClass = "form-control";
txt_desc.Attributes.Add("placeholder", "Enter day " + i + " description");
txt_desc.TextMode = TextBoxMode.MultiLine;
panel.Controls.Add(txt_desc);
}
}
and call this this way from your code behind:
add_tour tour_obj = new add_tour();
int days_count = 2;
var textBoxes = tour_obj.textbox_generator(days_count, itinerary_panel);
This works because itinerary_panel actually is a reference to the panel. See Passing Objects By Reference or Value in C#. However, it's often a bad idea to have a method modify the state in that manner.
Some inits done earlier in the code...
private List<System.Windows.Forms.TabPage> tab_pages = new List<System.Windows.Forms.TabPage>();
int tab_increment = 0;
Somewhere in the code, I create a bunch of tab pages in real-time.
for (i=0; i<5; i++)
{
tab_pages.Add( new System.Windows.Forms.TabPage() );
tab_pages[tab_increment].Location = new System.Drawing.Point(4, 22);
tab_pages[tab_increment].Name = 1 + tab_increment.ToString();
tab_pages[tab_increment].Size = new System.Drawing.Size(501, 281);
tab_pages[tab_increment].Text = tab_increment.ToString();
this.tabControl.Controls.Add(tab_pages[tab_increment]);
tab_increment += 1;
}
Now I would like to access elements that are these tab pages. Also let's pretend that I created different elements on each page (example, tabPage[0] a button, tabPage[1] a checkbox, etc), how do I access them knowing that everything was added dynamically?
Check this approach:
void Walk(Control control)
{
foreach (Control c in control.Controls)
{
//just walking through controls...
//...do something
//but remember, it could contain containers itself (say, groupbox or panel, etc.)...so, do a recursion
if (c.Controls.Count > 0)
Walk(c);
}
//or
foreach (Button btn in control.Controls.OfType<Button>())
{
//an example of how to walk through controls sub array of certain type
//this loop won't have a single iteration if this page contains no Buttons
//..so you can replace Button
//and have some certain code for different types of controls
}
}
And launch it for tabcontrol:
foreach (TabPage page in tabControl1.TabPages)
Walk(page);
I guess there is no special need to have separate collection of tabpages for one tabcontrol, as soon as it has TabPages property.
In the code above I used Enumerable.OfType Method to get a subcollection of controls of certain type.
As for your code, try this:
for (int i = 0; i < 5; i++)
{
this.tabControl.Controls.Add(new System.Windows.Forms.TabPage());
this.tabControl.TabPages[i].Text = i.ToString();
//...do whatever you need
//...
//besdies, I think, ther's no need in tab_increment...loop index works well enough
}
In order to add pages, I think that using
tabControl.TabPages.Add(new TabPage("Name"));
or in your case
this.tabControl.TabPages.Add(tab_pages[tab_increment]);
is more suitable.
In order to access them you could use
TabPage tp = tabControl.TabPages[i]; //where i is the index of your TabPage
and you can use TabPage.Controls.Add of the Controls property to add any Control on the TabPage like:
Button btn = new Button();
btn.Name = "Button name";
tp.Controls.Add(btn);
You can use the Controls property on the TabPage object. Each control in the collection is given to you as a Control, and it is up to you to cast them to the type that you want.
On one web user control
public void displayFindingSection(int sectionsid,string text,string head)
{
SectionHeading.Text = head;
DataSet totImgs;
totImgs = objGetBaseCase.GetFindingsNewerImages(sectionsid);
FindingViewerlist.DataSource = totImgs;
DataBind();
SectionText.Text = text;
}
On other web user control
public void DisplayFindingsViewer(CipCaseWorkflowItem2 item)
{
FindingViewerDisplay.Visible = true;
ImageAndSimpleViewer.Visible = false;
objGetBaseCase.GetFindingsImages((Convert.ToInt32(Session["CaseId"])), item.ItemId);
FindingsViewerNew = objGetBaseCase.GetFindingViewerNewElementDetails(item.ItemId);
for (int i = 0; i < FindingsViewerNew.Count; i++)
{
FindingViwerDisplay uc = (FindingViwerDisplay)LoadControl("FindingViwerDisplay.ascx");
FindingPlaceholder.Controls.Add(uc);
uc.displayFindingSection(Convert.ToInt32(FindingsViewerNew[i].Index), FindingsViewerNew[i].Text, FindingsViewerNew[i].Title);
}
}
I am adding the all the image in user control and displaying the image, but when i am using the above code, web user control is also adding every time and one image is showing in in control what i want is all images should show in only one user control.. sectionsid is getting the image id from the database. I think prob with for loop but i am unable to solve it.. help me it that
Might be it is happening u have defined it inside the loop
FindingViwerDisplay uc = (FindingViwerDisplay)LoadControl("FindingViwerDisplay.ascx");
FindingPlaceholder.Controls.Add(uc);
On Each loop you are adding uc and calling displayFindingSection whcich ofcouse add 1 image than loop go back add a new control again and than add one image it will go on till your loop completion so add control once before loop and call just displayFindingSection in loop..
Do this,
FindingViwerDisplay uc = (FindingViwerDisplay)LoadControl("FindingViwerDisplay.ascx");
FindingPlaceholder.Controls.Add(uc);
//define here a dataTabel with three columns let say u have datatable dt
for (int i = 0; i < FindingsViewerNew.Count; i++)
{
dt.Rows.Add(Convert.ToInt32(FindingsViewerNew[i].Index), FindingsViewerNew[i].Text, FindingsViewerNew[i].Title);
}
uc.displayFindingSection(dt);
Then work out on that dt in displayFindingSection
Sorry if i am wrong...
I have an input field on my page where the user will type in the number of text inputs they want to create. The action for the button is:
int num_flds = int.Parse(a_fld.Text);
for (int i = 0; i < num_flds; i++)
{
TextBox tmp = new TextBox();
tmp.ID = "answer_box" + i;
tmp.Width = Unit.Pixel(300);
answer_inputs.Controls.Add(tmp);
}
Now, I have another button that the user would click after they have filled in all their dynamically-created text boxes. Questions, first of all, am I creating the text boxes dynamically in the correct place? How would I get the values out of the dynamically-created text boxes? (The dynamically-created text boxes are being added to the Panel "answer_inputs".
I recommend reading this and a few other articles about the topic of dynamically created controls. It is not quite as straightforward as you might think. There are some important page lifecycle issues to consider.
When creating web controls dynamically, I find it best to have the controls themselves report in the answers. You can achieve it like this:
Create something in your Page class to store the values:
private readonly Dictionary<TextBox, string> values=new Dictionary<TextBox, string>();
Make a method to act as a callback for the textboxes when their value changes:
void tmp_TextChanged(object sender, EventArgs e)
{
TextBox txt = sender as TextBox;
if(txt!=null)
{
values.Add(txt,txt.Text);
}
}
And then add this method to each textbox as they are added:
int num_flds;
if(!int.TryParse(a_fld.Text,out num_flds))
{
num_flds = 0;
}
for (int i = 0; i < num_flds; i++)
{
TextBox tmp = new TextBox();
tmp.ID = "answer_box" + i;
tmp.Width = Unit.Pixel(300);
answer_inputs.Controls.Add(tmp);
tmp.TextChanged += tmp_TextChanged;
}
Finally, you iterate through the dictionary on callback to see if it holds any values. Do this in the OnPreRender method for instance.
Edit: There is a problem with this, if the number of text fields are decreased on postback. Some safe way to recreate the previous textfields on postback should be employed.