Using FindControl: Accessing Controls in a Formview - asp.net

I'm developing a simple Wedding List application, where guests can reserve the present they want to buy for the bride and groom. The Reserve page wraps a few fields inside a couple of panels, all wrapped inside a FormView.
The user enters their name, email and the quantity of items that they want to reserve, and the page will make the necessary reservations in the DB.
My first problem was that in FormView_ItemCommand, I couldn't reference any of the other controls in the FormView.... I figured this was a case for FindControl - but why do I need to for a Formview when I've never needed it for ListViews or DetailViews?
Secondly, I know the following code works..
Dim oCtrl as TextBox = Me.fvwReservation.FindControl("txtEmail")
Dim Test As String = oCtrl.Text
...but why can't I use...
Dim Test As String = Me.fvwReservation.FindControl("txtEmail").Text
??
Finally, I don't think I need it on this occasion, but I've been researching recursive FindControl variants, but I haven't actually found one that actually compiles! Any suggestions?
It's a lot for one post - thanks in advance.
Gratuitous Code Snippet:
<asp:FormView ID="fvwReservation" runat="Server" DataSourceID="dsGift">
<ItemTemplate>
<asp:Panel runat="server" ID="pnlDetails">
<h3>Reserve Item: <%#Eval("ShortDesc")%></h3>
<p>You have chosen to reserve the <em><%#Eval("LongDesc")%></em> gift.</p>
<p>Please enter your details below to confirm the reservation.</p>
</asp:Panel>
<asp:Panel runat="server" ID="pnlConfirm">
<div class="row">
<asp:Label runat="server" CssClass="label">Name:</asp:Label><asp:TextBox ID="txtName" MaxLength="50" runat="server" CssClass="Field" />
<asp:RequiredFieldValidator ID="rfvName" runat="server" ErrorMessage="You must specify your Name" ControlToValidate="txtName" />
</div>
<div class="row">
<asp:Label runat="server" CssClass="label">Email:</asp:Label><asp:TextBox ID="txtEmail" MaxLength="100" runat="server" CssClass="Field"/>
<asp:RequiredFieldValidator ID="rfvEmail" runat="server" ErrorMessage="You must specify your Email Address" ControlToValidate="txtEmail" />
<asp:RegularExpressionValidator ID="regexEmail" ValidationExpression="^(([A-Za-z0-9]+_+)|([A-Za-z0-9]+\-+)|([A-Za-z0-9]+\.+)|([A-Za-z0-9]+\++))*[A-Za-z0-9]+#((\w+\-+)|(\w+\.))*\w{1,63}\.[a-zA-Z]{2,6}$" runat="server" ErrorMessage="Please enter a valid Email Address" ControlToValidate="txtEmail" />
</div>
<div class="row">
<asp:Label runat="server" CssClass="label">Quantity (max <%#Eval("QtyRemaining")%>):</asp:Label><asp:TextBox ID="iQty" MaxLength="2" runat="server" CssClass="Field" />
<asp:RangeValidator ID="rvQty" runat="server" ErrorMessage="The Quantity mmust be between 1 and 10" MinimumValue="1" MaximumValue="10" ControlToValidate="iQty" />
</div>
<div class="row">
<asp:Label runat="server" CssClass="label"> </asp:Label>
<asp:Button ID="btnReserve" Text="Confirm Reservation" CommandName="Reserve" runat="server" />
</div>
</asp:Panel>
</ItemTemplate>
</asp:FormView>

For your second question, FindControl returns a generic Control, and must be cast to the specific type of control in order to obtain access to the properties of that specific type of control.
You can do it in a one liner, like this:
Dim Test As String = CType(Me.fvwReservation.FindControl("txtEmail"), TextBox).Text
Regarding your first question, I would love to know the answer to that as well.
EDIT
Looked through a few other StackOverflow responses (specifically this one and this one). As the controls in the FormView template do not exist until the template is the active template, you cannot directly refer to them in the code behind. Thus, you must use FindControl during an appropriate event to access the controls.

Hmm, even in the FormView templates, I don't think that FindControl will work reliably, typically I would only use that with straight HTML rendered controls, not ASP.net generated ones.
I'm pretty sure that the templated controls should be available in the Server side code, (ie. txtEmail.text) if not, double check the template
A recursive FindControl is also pretty taxing on the Server and potentially unreliable.

You need to use recursive FindControl method in order to access the elements inside the FormView control. There are many implementations available and one of them is linked below:
http://www.highoncoding.com/Articles/606_Creating_a_BetterFindControl_and_MuchBetterFindControl.aspx

Related

How can I achieve the effect of multiple validation groups on a single validation control?

I need to be able to apply multiple validation groups to some of the controls on my page, because for each of the three submit "modes", there is a different set of required fields.
I have three submit buttons, and each one has its own validation group (reject, approve, and save). "Reject" doesn't actually have any required fields currently, but may in the future. "Save" only requires "first name" and "last name", while "approve" requires "first name", "last name", as well as "group name".
I tried simply putting multiple validation groups in the attribute value (as in the code below), but the validation didn't fire at all.
I also tried not specifying a group at all in an attempt to just have the validation always fire, but again again, it didn't fire at all.
<div>
<label for='<%= txt_FirstName.ClientID %>'>First Name</label>
<asp:TextBox ID="txt_FirstName" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="rfv_FirstName" runat="server" text="Required"
ControlToValidate="txt_FirstName" ValidationGroup="approve save">
</asp:RequiredFieldValidator>
</div>
<div>
<label for='<%= txt_LastName.ClientID %>'>Last Name</label>
<asp:TextBox ID="txt_LastName" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="rfv_LastName" runat="server" text="Required"
ControlToValidate="txt_LastName" ValidationGroup="approve save">
</asp:RequiredFieldValidator>
</div>
<div>
<label for='<%= ddl_GroupName.ClientID %>'>Group Name</label>
<asp:DropDownList ID="ddl_GroupName" runat="server"></asp:DropDownList>
<asp:RequiredFieldValidator ID="rfv_GroupName" runat="server" text="Required"
ControlToValidate="ddl_GroupName" ValidationGroup="approve">
</asp:RequiredFieldValidator>
</div>
<div>
<asp:Button ID="btn_Reject" runat="server" Text="Reject"
ValidationGroup="reject" OnClick="btn_Reject_Click" />
<asp:Button ID="btn_Approve" runat="server" Text="Approve"
ValidationGroup="approve" OnClick="btn_Approve_Click" />
<asp:Button ID="btn_Save" runat="server" Text="Save"
ValidationGroup="save" OnClick="btn_Save_Click" />
</div>
I'm certain I can achieve the desired effect with some additional code, or duplicated validator controls for each validation group, but I was hoping the webforms framework would have a simpler, built-in way to do this.
UPDATE (2018-01-02):
The question "Is it possible to assign Multiple Validation Groups to a single Validation Control?" is a special case of my own. It has a single control in multiple groups, whereas I have multiple controls with multiple overlapping groups. Additionally, the answer proposes having a validation control for each input/group combination. This is a terrible solution because, among other things, it violates the DRY (don't repeat yourself) programming principle and makes maintenance/enhancements more difficult.
The above also links the question "How to validate against Multiple validation groups?". That question is a completely different issue (validation groups within validation groups), and its answer proposes custom javascript that would need to be written for every submit button, on every page that requires multiple validation groups.
I am looking for a general case solution that I can write/implement once and apply to the entirety of the web application, and thus I do not consider my question a duplicate of the above mentioned questions.
UPDATE (2018-01-03):
Between other questions/articles I've encountered while researching my problem, as well as the gracious assistance of a.bajorinas and Sunil, I've established that it is not possible to have multiple validation groups on a validation control out-of-the-box, and custom code will be required to achieve the desired effect. I've updated the question accordingly, to assist anyone looking to achieve this in the future.
I'll be testing a solution that incorporates elements from both a.bajorinas' and Sunil's answers and will hopefully be able to provide an update afterward.
The only thing I can think of for your desired use case, is setting ValidationGroup for your validators in code behind on button click, keep in mind that this would first perform a postback and then validate the controls which might not be ok for you.
protected void btn_save_click(object sender, EventArgs e){
rfv_FirstName.ValidationGroup = "save";
Page.Validate("save");
if (Page.IsValid)
{
//logic if validators pass
}
}
This will let you reuse validators for multiple groups.
Also in my linked posted, one of the comments to the selected answer is "It is not possible to assign multiple groups to a validation control"
ASP.Net does not support multiple validation groups. However, with a little bit of JavaScript code you can make it support multiple validation groups.
What you need to do is override the standard JavaScript function of IsValidationGroupMatch. This function is part of the standard validation library in ASP.Net.
At bottom of your aspx page, just add the script tag given below. Note that this script is just before closing form, body and html tags, which is important when overriding a JavaScript function.
<script type="text/javascript">
window["IsValidationGroupMatch"] = function (control, validationGroup) {
if ((typeof (validationGroup) == "undefined") || (validationGroup == null)) {
return true;
}
var controlGroup = "";
var isGroupContained = false;
if (typeof (control.validationGroup) == "string") {
controlGroup = control.validationGroup;
var controlGroupArray = [];
if (validationGroup.indexOf(",") > -1) {
controlGroupArray = validationGroup.split(",");// validationGroup.split(",");
}
for (var i = 0; i < controlGroupArray.length; i++) {
if (controlGroupArray[i].trim() == controlGroup.trim()) {
isGroupContained = true;
}
}
}
return (controlGroup == validationGroup || isGroupContained);
}
</script>
</form>
</body>
</html>
Once you do this, then you can add a comma delimited list of validation groups for the button that validates multiple validation groups as in example below. In example below a button with id of btnMultipleValidationGroups is validating group1 as well as group2.
<div>
TextBox1 :
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ErrorMessage="TextBox1 needs input" ControlToValidate="TextBox1" ForeColor="Red" ValidationGroup="group1"></asp:RequiredFieldValidator>
<br />
<br />
TextBox2 :
<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ErrorMessage="TextBox2 needs input" ControlToValidate="TextBox2" ForeColor="Red" ValidationGroup="group2"></asp:RequiredFieldValidator>
<br />
<br />
TextBox3 :
<asp:TextBox ID="TextBox3" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server" ErrorMessage="TextBox3 needs input" ControlToValidate="TextBox3" ForeColor="Red" ValidationGroup="group3"></asp:RequiredFieldValidator>
<br />
<br />
</div>
<asp:Button ID="btnMultipleValidationGroups" runat="server" Text="Validate group1 and group2" ValidationGroup="group1,group2" OnClick="btnMultipleValidationGroups_Click" />
<asp:Button ID="btnGroup1" runat="server" Text="Validate only group1" ValidationGroup="group1" OnClick="btnGroup1_Click" />
<asp:Button ID="btnGroup2" runat="server" Text="Validate only group2" ValidationGroup="group2" OnClick="btnGroup2_Click" />

PNM Sequence & asp.net: GridTemplateColumn should be mandatory

I use PNM Sequence. And I need to make one grid column as the mandatory field.
I know how to make it with any separate control. E.g. I can type:
<sq8:GridBoundColumn DataField="txtField" HeaderText="txtField"
SortExpression="txtField" UniqueName="txtField" FilterControlAltText="">
<ColumnValidationSettings>
<RequiredFieldValidator ForeColor=""></RequiredFieldValidator>
</ColumnValidationSettings>
</sq8:GridBoundColumn>
And I can use this Validator for the TextBox:
<sq8:Label runat="server" Text="Field:" ID="Label1" Width="100%"></sq8:Label>
<nobr>
<sq8:TextBox runat="server" ID="txtField" Width="100%"></sq8:TextBox>
<sq8:RequiredFieldValidator runat="server"
ErrorMessage="RequiredFieldValidator"
ID="RequiredFieldValidator4"
ControlToValidate="txtField"
SetFocusOnError="True">*</sq8:RequiredFieldValidator>
</nobr>
<sq:BindableControl runat="server" TargetControlID="txtField"
DataField="txtField"></sq:BindableControl>
And it works. User can't send the form because he gets an error - the field is empty.
But I need to do the same with grid.
When I open "Edit columns" in Grid Wizard I can't see any property as "mandatory" or something like this.
And the code with RequiredFieldValidator doesn't work with a grid column. If I try to use it:
<Columns>
<sq8:GridBoundColumn DataField="txtFieldGrid" HeaderText="txtFieldGrid"
SortExpression="txtFieldGrid" UniqueName="txtFieldGrid"
FilterControlAltText="">
<sq8:RequiredFieldValidator runat="server"
ErrorMessage="RequiredFieldValidator"
ID="RequiredFieldValidator4"
ControlToValidate="txtFieldGrid"
SetFocusOnError="True">*</sq8:RequiredFieldValidator>
<sq:BindableControl runat="server" TargetControlID="txtFieldGrid"
DataField="txtFieldGrid"></sq:BindableControl>
</sq8:GridBoundColumn>
</Columns>
In this case, I have an error:
Is there some method for grid column validation? Or it's impossible with a grid?
Maybe I can use some javascript?

Validation Summary not picking up Error Message in group

I have several required fields and regex's on my form. The validation is fired on a button click. When the button is clicked, the error messages are showing where the asp:RequiredField are declared and not in the validation summary. Here is my code:
Validation Summary:
<asp:ValidationSummary id="mySummary" DisplayMode="List" HeaderText="Error:" EnableClientScript="true" ShowSummary="true" runat="server" ValidationGroup="valGroup" />
Required Fields/Regex:
<!-- Required -->
<asp:RequiredFieldValidator ID="reqField1" ControlToValidate="txtSomething" ErrorMessage="Something is required" runat="server" Display="Static" InitialValue="" ValidationGroup="valGroup" />
<!-- Regex -->
<asp:RegularExpressionValidator runat="server" id="regexField1" ControlToValidate="txtSomething"
ErrorMessage="Something in the wrong format." ValidationExpression="^([\w-]+(?:\.[\w-]+)*)#((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$" ValidationGroup="valGroup">
</asp:RegularExpressionValidator>
Button:
<asp:LinkButton ID="btnValidate" runat="server" CausesValidation="True" ValidationGroup="valGroup" >Validate</asp:LinkButton>
Any suggestions?
It's hard to tell from this, as it does look like it's setup correctly to me. The only way to debug is to check the Page.Validators collection, find the validators in there, and ensure IsValid is false for those guys. All the ValidationSummary does is check this collection, and for any with a matching validation group, if the IsValid property is false, adds it to the list that's rendered out.

asp.net required field validation called on every button action

I wrote a simple asp.net code with the asp.net required validator control, the problem is that I only have one submit button called GO, and a dropdownlist that looks for the selection :
clear, submit, cancel.
No matter what option is selected, the required field validation is being fired.
Is there a way to code the page so only when the selected value is Submit it validates?
<asp:TextBox runat="server" id="txtName" />
<asp:RequiredFieldValidator runat="server" id="reqName" controltovalidate="txtName" errormessage="Please enter your name!" />
<br /><br />
<asp:DropDownList ID="dpAction" runat="server">
<asp:ListItem>Submit</asp:ListItem>
<asp:ListItem Value="Reset">Reset</asp:ListItem>
<asp:ListItem>Cancel</asp:ListItem>
</asp:DropDownList>
<asp:Button ID="btnAction" runat="server" onclick="btnAction_Click" Text="Go"
Width="40px" />
You will probably have to use a custom validator, and you would need to write the client side code for it also if you want client side validation.
I'm assuming you have a text box or something else that is required when "dpAction" is set to "Submit"?
So for example you would do something like this in your markup
<asp:CustomValidator id="CustomValidator1" runat="server"
OnServerValidate="TextValidate"
ControlToValidate="TextBox1"
ErrorMessage="Text must be specified if Submit is selected">
and in your code-behind
protected void TextValidate(object source, ServerValidateEventArgs args)
{
args.IsValid = dpAction.SelectedValue == "Submit" && !String.IsNullOrEmpty(textbox1.Text);
}
using "required" attribute.
its new in html 5
you should set ValidationGroup for each Validator!
for all controls that you want to be validated and the button to fire the validation:
and the button must have same validaton group with your validator!

AutoPostBack on CheckBox control sometimes fails

If have the below markup.
<asp:checkbox id="chkTVLic" runat="server" text="TV Licence" oncheckedchanged="chkDocs_CheckChanged"
autopostback="true" CausesValidation="false" />
<asp:panel id="pnlTVLic" runat="server" visible="false">
<div class="toggle-item-link1 document-date">
<asp:panel id="pnlTVLicIssueDate" runat="server">
<p>
Please enter the date of issue
</p>
<div class="fm-req">
<asp:textbox id="txtTVLicIssueDate" cssclass="tb size2" runat="server" onblur="return true;"></asp:textbox>
<cc2:calendarextender id="caleTVLicIssueDate" runat="server" targetcontrolid="txtTVLicIssueDate"
popupbuttonid="ibnTVLicIssueDate" popupposition="BottomLeft" animated="true"
format="dd/MM/yyyy">
</cc2:calendarextender>
<asp:imagebutton id="ibnTVLicIssueDate" runat="server" imageurl="../images/img-calendar-day.png"
alternatetext="Calendar" tooltip="Pick Date" cssclass="date-picker" />
<asp:requiredfieldvalidator id="rfvTVLicIssueDate" CssClass="error" runat="server" controltovalidate="txtTVLicIssueDate"
display="Dynamic" errormessage="Required" setfocusonerror="true" validationgroup="TVLic"></asp:requiredfieldvalidator>
<asp:comparevalidator id="cmvTVLicIssueDate" CssClass="error" runat="server" errormessage="Not a valid date"
controltovalidate="txtTVLicIssueDate" operator="DataTypeCheck" type="Date" setfocusonerror="true"
validationgroup="TVLic" display="Dynamic" cultureinvariantvalues="true"></asp:comparevalidator>
<asp:customvalidator id="cuvTVLicIssueDate12Months" CssClass="error" runat="server" controltovalidate="txtTVLicIssueDate"
validationgroup="TVLic" display="Dynamic" onservervalidate="cuvDocIssueDate12Months_ServerValidate"
errormessage="Document must be less than 12 months old."></asp:customvalidator>
</div>
</asp:panel>
<asp:panel id="pnlTVLicApprove" runat="server">
<asp:LinkButton id="lbnTVLicApprove" runat="server" CssClass="screen-hide"
alternatetext="Confirm TV Licence" tooltip="Confirm TV Licence" Text="OK" CausesValidation="false" OnClick="lbnApproveConfirm_Click" />
<asp:imagebutton id="ibnTVLicApprove" runat="server" imageurl="../images/img-accept-doc-off.png"
alternatetext="Approve" tooltip="Approve" cssclass="approval-btn" causesvalidation="true" validationgroup="TVLic" OnMouseDown="HandleApproveClick('TVLic','lbnTVLicApprove');return false;" OnClientClick="HandleApproveClick('TVLic','lbnTVLicApprove');return false;" />
<span class="approval-label">Accept document:</span></asp:panel>
</div>
</asp:panel>
The app is written in c# but i havn't posted any actual code as all the user code related to this markup seems to work fine.
The problem is the CheckBox chkTVLic has causes validation set to false and autopostback set to true. So whatever happens when i check and uncheck the checkbox it should postback. Most of the time this is exactly what it does and the result is to show and hide pnlTVLic when it is checked and unchecked. However if any on the validators within the panel fire, the checkbox does not cause a postback the first time. It will on all subsequent times but never the first. However it should ALWAYS cause a postback. What could be stopping it. Before someone asks there is no use written client side code, everything is pure .net markup and c# code.
I don't see why it shouldn't postback when you check/uncheck the checkbox, but if the only purpose of that checkbox is to hide/unhide a panel, I would rather do it in javascript. Doing a full postback to the server just for hiding some panel seems really bad.
In javascript you can do this to hide the panel:
document.getElementById('<%=pnlTVLic.ClientID%>').display='none';
And this to show it:
document.getElementById('<%=pnlTVLic.ClientID%>').display='block';
It's going to be so much faster and better. Just put a regular checkbox instead of the ASP.NET one and subscribe to the onclick event.
Sorry, one more comment:
I think you are wrong when you say that the checkbox should ALWAYS cause a postback. No, if one of the validators fires inside the panel, the checkbox will not cause a postback until the condition is satisfied.
This is what I did and it worked.
on checkbox onclick event I disabled all the validation controls and immediately did Page_ClientValidate(); and it worked.

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