Develop Reference

Retrieve TextBox By Name

In my project i know the names of TextBoxes which are dynamically generated is there any solution to retrieve this TextBox text from other methods.In other sense i want to get TextBox by name and want to use in other part of code.
I have TextBox allocated like this...
private void Met(string rowNo)
{
TextBox t2 = new TextBox();
t2.Name = "itemAmt" + rowNo;
PurchaseItemEntryDyPanel.Controls.Add(t2);
}
Is there any way other than using name? Any Solution?

I personaly use name when I want to read posted data from a form.
And I would use Id when controls are supposed to be unique. So the code is a little different:
var t2 = new TextBox();
t2.ID = "itemAmt" + rowNo;
//since you mention in the comments, add it to the panel
yourPanel.Controls.Add(t2);
Then to get the textBox value
var controlId = "itemAmt" + rowNo;
var t2 = ((TextBox)(yourPanel.FindControl(controlId)));
if(t2 != null)
{
//do someting
//t2.Text = "something";
//t2.Enabled = true;
}
If you are not willing to make that change, go over the solution posted earlier.

You can get your TextBox from Controls collection of Form by it's name like this:
var myTextBox = this.Controls[textBoxName];

You don't show too much of your code, but I assume you're adding it to the collection of controls on your form. Otherwise, the TextBox you create in Met goes out of scope when your method ends, just like any other local variable.
private void Met(string rowNo)
{
TextBox t2 = new TextBox();
t2.Name = "itemAmt" + rowNo;
this.Controls.Add(t2); // need to add the TextBox to your form's controls
}
Then you can use Selman22's solution or, if the control might be added to a GroupBox or Panel, you'll want to search all child controls too:
var myControl = this.Controls.Find("itemAmt4", true);
if (myControl != null)
myControl.Enabled = true;

Use this in your Class:
foreach (Control tempCtrl in this.Controls)
{
// Determine he control is textBox1,
if (tempCtrl.Name == "itemAmt" + rowNo)
{
this.Controls.Remove(tempCtrl);
}
}

rangevalidator c# how to use later in code

I created a range validator and would like to trigger it once the submit button was clicked.
RangeValidator rv_tbAbsenceDay = new RangeValidator();
rv_tbAbsenceDay.ID = "rv_tbAbsenceDay" + tbAbsenceDay.ID;
rv_tbAbsenceDay.ControlToValidate = tbAbsenceDay.ID;
rv_tbAbsenceDay.EnableClientScript = true;
rv_tbAbsenceDay.Display = ValidatorDisplay.Dynamic;
rv_tbAbsenceDay.MinimumValue = DateTime.Now.AddMonths(-6).ToString("d");
rv_tbAbsenceDay.MaximumValue = DateTime.Now.ToString("d");
rv_tbAbsenceDay.ErrorMessage = "Date cannot be older than 6 months and not in the future.";
rv_tbAbsenceDay.SetFocusOnError = true;
plcMyStaff.Controls.Add(rv_tbAbsenceDay);
plcMyStaff is a placeholder.
<asp:PlaceHolder ID="plcMyStaff" runat="server"></asp:PlaceHolder>
How do I get hold of the created range validator to trigger it i.e. rv.validate(); ?
I have tried this:
protected void MarkAsSick_Command(Object sender, CommandEventArgs e)
{
DropDownList tempddlReason = (DropDownList)plcMyStaff.FindControl("ddlReason" + e.CommandArgument.ToString());
TextBox temptbAbsenceDay = (TextBox)plcMyStaff.FindControl("tbAbsenceDay" + e.CommandArgument.ToString());
TextBox temptbLastDayWorked = (TextBox)plcMyStaff.FindControl("tbLastDayWorked" + e.CommandArgument.ToString());
RangeValidator temprv_tbAbsenceDay = (RangeValidator)plcMyStaff.FindControl("rv_tbAbsenceDay" + e.CommandArgument.ToString());
temprv_tbAbsenceDay.validate();
...
Hope you can help me.
thanks,
Andy

First off to debug this I would suggest examining the plcMyStaff object in which you are adding the control to see if it does in fact contain the control you wish to access.
You should be able to retrieve it from the Page object that your webform inherits.
Page.FindControl();
// Or you can Iterate through each control to see what the control is called and test for the name you want
foreach (var control in Page.Controls)
{
}

Can't Add RegularExpressionValidator to Panel

I'm having an issue with programmatically adding a RegularExpressionValidator to any Container control (Panel, Placeholder, etc.). Here is my code:
// Get the path of the file on the server
string page = Page.Request.FilePath;
int managementCompanyId = Convert.ToInt32(Session["ManagementCompanyId_AddResident"].ToString().Trim());
// Get field validation details
Collection<ExportFieldValidation> details = ValidationBL.GetValidationDetails(managementCompanyId, page);
ContentPlaceHolder body = Page.Form.FindControl("ContentBody") as ContentPlaceHolder;
foreach (ExportFieldValidation detailItem in details)
{
// Check if the control exists on the page
TextBox control = body.FindControl(detailItem.FieldToValidate) as TextBox;
if (control != null)
{
RegularExpressionValidator regex = new RegularExpressionValidator()
{
ControlToValidate = control.UniqueID.ToString(),
ID = detailItem.ValidatorFieldName,
ValidationExpression = detailItem.RegularExpression,
Page = this,
SetFocusOnError = true,
Text = detailItem.ErrorMessage,
Enabled = true,
EnableViewState = true,
CssClass = "Error"
};
Panel validationPanel = body.FindControl("PanelAddResident") as Panel;
validationPanel.Controls.Add(regex);
}
}
When I go to the page I get the error Unable to find control id 'myControl' referenced by the 'ControlToValidate' property of 'RegularExpressionValidatorResidentId', where my control is the control.UniqueID.ToString() from above, which we store in the database and is for sure correct, as I've double-, triple- and quadruple-checked the value.
However, if I replace validationPanel.Controls.Add(regex); with Page.Form.Controls.Add(regex); everything works perfectly.
Is there a way to add my validator to the container? I'm sure I'm just doing something wrong or missing a step in the middle somewhere. Any help would be greatly appreciated.

This part is wrong:
ControlToValidate = control.UniqueID.ToString()
You need to use this:
ControlToValidate = control.ID;
You must provide an ID for control before.
UniqueID is the name the component will have in the client but Validator Controls use the server side control name to do this.

Asp.Net Get Control Values from PlaceHolder

I have defined a placeholder in my page like this;
<asp:PlaceHolder ID="attrPlaceHolder" runat="server"></asp:PlaceHolder>
I am populating this place holder from a database table using query string productId like this;
// obtain the attributes of the product
DataTable attrTable = CatalogAccess.GetProductAttributes(productId);
// temp variables
string prevAttributeName = "";
string attributeName, attributeValue, attributeValueId;
// current DropDown for attribute values
Label attributeNameLabel;
DropDownList attributeValuesDropDown = new DropDownList();
// read the list of attributes
foreach (DataRow r in attrTable.Rows)
{
// get attribute data
attributeName = r["AttributeName"].ToString();
attributeValue = r["AttributeValue"].ToString();
attributeValueId = r["AttributeValueID"].ToString();
// if starting a new attribute (e.g. Color, Size)
if (attributeName != prevAttributeName)
{
prevAttributeName = attributeName;
attributeNameLabel = new Label();
attributeNameLabel.Text = "<li class=\"txt\">" + attributeName + ":</li>";
attributeValuesDropDown = new DropDownList();
attrPlaceHolder.Controls.Add(attributeNameLabel);
attrPlaceHolder.Controls.Add(attributeValuesDropDown);
}
// add a new attribute value to the DropDownList
attributeValuesDropDown.Items.Add(new ListItem(attributeValue, attributeValueId));
}
However, when inside a button click event, when I loop through this place using visual studio debugging, I saw that the visual studio studio debugger first hit the "attrPlaceHolder.Controls" word in my foreach loop, then secondly comes to 'in' keyword (in foreach loop) but it isn't hitting the first two words (i-e 'Control cnt' in my foreach loop. Here it looks;
protected void ButtonBuyNow_Click(object sender, EventArgs e)
{
// Retrieve the selected product options
string options = "";
foreach (Control cnt in attrPlaceHolder.Controls)
{
if (cnt is Label)
{
Label attrLabel = (Label)cnt;
options += attrLabel.Text;
}
if (cnt is DropDownList)
{
DropDownList attrDropDown = (DropDownList)cnt;
options += attrDropDown.Items[attrDropDown.SelectedIndex] + "; ";
}
}
// Add the product to the shopping cart
ShoppingCartAccess.AddItem(productId, options);
}
Basically I need 'options' variable to be populated but it isn't hitting the foreach loop inside, therefore I am not able to get the 'options' variable populated.
This is a serious problem in my application. Please tell me why I can't get the inside the foreach loop.
NOTE:
please note that this isn't the complete code of my entire page. My rest of the code executes correctly.

why I can't get the inside the foreach loop
Because the list is empty.
Why is the list empty? (Would be the next logical question)
Because, at ASP.Net, dynamically created controls must be re-created at Page_Init in order to exist. When you create them at this stage, the page lifecycle will bind the viewstate and will be ready for use.
If you receive a postback (from the button, for example) and don't recreate them, they simply don't exist.

C# dynamically created control issue

i'm having issues retreiving the values out of a dynamically created dropdownlist. all controls are created in the Page_Init section. the listitems are added at that time as well from an array of listitems. (the controls are named the same so should be accessable to the viewstate for appropriate setting.)
here is the function that attempts to retrieve the values:
protected void Eng98AssignmentComplete_Click(object sender, EventArgs e)
{
String myID = "0";
Page page = Page;
Control postbackControlInstance = null;
// handle the Button control postbacks
for (int i = 0; i < page.Request.Form.Keys.Count; i++)
{
postbackControlInstance = page.FindControl(page.Request.Form.Keys[i]);
//Response.Write(page.Request.Form.Keys[i].ToString());
if (postbackControlInstance is System.Web.UI.WebControls.Button)
{
myID = Convert.ToString(
postbackControlInstance.ID.Replace("button_", ""));
}
}
String txtholder = "ctl00$ContentPlaceHolder$Eng098Instructors_" + myID;
Response.Write("MYID: " + myID + "<br/>");
DropDownList ddInstructorCheck = (DropDownList)Page.FindControl(txtholder);
Response.Write("Instructor Selected: "
+ ddInstructorCheck.SelectedValue + "<br/>");
}
here is the output I get, no matter which instructor was selected.....
MYID: 1_1
Instructor Selected: 0
ctl00$ContentPlaceHolder$Eng098Instructors_1_1
the name of the control is correct (verified via view source)....
ideas?

You're going to a lot of work to build this fancy string:
ctl00$ContentPlaceHolder$Eng098Instructors_1_1
That is the client ID of your control, not the server id. This code is running on the server side, and so you need the server id. To get that control using the server id, you need to do this:
ContentPlaceHolder.FindControl("Eng08Instructors_1_1");
Notice I didn't look in the page, because your content place holder created a new naming container.
Also, the way your loop is set up the myID variable will always end up holding the last button in the Keys collection. Why even bother with the loop?
Based on your comments, a better way to find the id of the dropdownlist is like this:
string id = ((Control)sender).ID.Replace("button_", "Eng098Instructors_");

why not just save the control in an instance in your class so that you don't have to use FindControl?

Do you also re-create the controls during the postback? Dynamically generated/added controls must be re-created with every request, they are not automatically re-created.

Why don't you cast the sender? This should be the button that caused the postback:
string myId = "0";
Button btn = sender as Button;
if (btn != null)
myId = btn.ID
...

You need to perform something like this because the UniqueID property is the key in Request.Form.
List<Button> buttons = new List<Button>();
List<DropDownList> dropdowns = new List<DropDownList>();
foreach (Control c in Controls)
{
Button b = (c as Button);
if (b != null)
{
buttons.Add(b);
}
DropDownList d = (c as DropDownList);
if (d != null)
{
dropdowns.Add(d);
}
}
foreach (String key in Request.Form.Keys)
{
foreach (Button b in buttons)
{
if (b.UniqueID == key)
{
String id = b.ID.Replace("button_", "");
String unique_id = "ctl00$ContentPlaceHolder$Eng098Instructors_" + id;
Response.Write("MYID: " + id + "<br/>");
foreach (DropDownList d in dropdowns)
{
if (d.UniqueID == unique_id)
{
Response.Write("Instructor Selected: " + d.SelectedValue + "<br/>");
break;
}
}
}
}
}

I'm not sure why you are generating the control in code (you can still add items dynamically if you do), but the code that generates the controls would probably be a huge help here. I'm guessing you are not setting the list item value, and instead just setting the list item text. Try seeing what you get from the SelectedText field and post your control creation function.
EDIT:
In response to your comment on #Martin's post, you said "yes I recreate the controls in the Page_Init function each time the page is created (initial or postback)". Are you also setting the selected value when you create them?
You can also use controls on the page even if your data comes from a database, the controls themselves don't have to be dynamically generated.

How about this?
((Button)sender).Parent.FindControl(myid)
Edit:I misunderstood your question. But i think you should follow page lifecycle. it is common issue for dynamically created controls.
I did some research and here is some info about Dynamically Created Controls may help you...

I had 2 catches.... here's what they were.
1. I didn't clear the table I was adding to before re-creating the controls.
apparently my attention to detail was off yesterday, i'm pretty sure the ctlXX frontrunner of the control was some different number upon postback due to how I was recreating the controls.
2. I was assigning the same list to all the dropdownlist controls.
once I called the lookup upon each creation a dropdownlist control, all works well.
anyway for what it's worth....