https://www.aspneto.com/Worked examples for ASP.NET Web Forms, C#, SQL Server, jQuery and CSS, checked against the official documentationhttps://www.aspneto.com/how-to-get-and-set-asp-net-textbox-value-using-javascript.htmlhttps://www.aspneto.com/how-to-get-and-set-asp-net-textbox-value-using-javascript.html2026-11-03How to read and change the text of an ASP.NET Web Forms TextBox from plain JavaScript: finding the rendered id with ClientID and ClientIDMode, the value property, multiline boxes, read-only and disabled boxes, and what the server sees after a postback.https://www.aspneto.com/how-to-get-and-set-asp-net-textbox-value-using-jquery.htmlhttps://www.aspneto.com/how-to-get-and-set-asp-net-textbox-value-using-jquery.html2026-11-02Using jQuery's val() to read and write an ASP.NET Web Forms TextBox: selectors that survive ClientID rewriting, reacting to input, setting values in GridView rows, and keeping the posted value on the server.https://www.aspneto.com/enable-disable-asp-net-textbox-on-button-click-event-in-jquery.htmlhttps://www.aspneto.com/enable-disable-asp-net-textbox-on-button-click-event-in-jquery.html2026-11-01Toggle an ASP.NET TextBox between enabled and disabled from a button click using jQuery's prop(), without an unwanted postback, and understand what disabled, readonly and the server-side Enabled property each do to the posted value.https://www.aspneto.com/set-asp-net-dropdownlist-selected-value-text-using-javascript-jquery.htmlhttps://www.aspneto.com/set-asp-net-dropdownlist-selected-value-text-using-javascript-jquery.html2026-10-31Select an item of an ASP.NET DropDownList from the browser by value or by visible text, with plain JavaScript and with jQuery, fire AutoPostBack when needed, and avoid event validation and 'multiple items selected' errors on the server.https://www.aspneto.com/sql-injections-what-is-sql-injection-and-how-to-prevent-it.htmlhttps://www.aspneto.com/sql-injections-what-is-sql-injection-and-how-to-prevent-it.html2026-10-30How SQL injection works, a vulnerable ADO.NET login query and how it is exploited, and the defences that actually work in C# and SQL Server: parameterised commands, safe stored procedures and sp_executesql, allow-lists for identifiers and least privilege.https://www.aspneto.com/100-frequently-asked-interview-questions-on-asp-net-sql-server-oop-concepts.htmlhttps://www.aspneto.com/100-frequently-asked-interview-questions-on-asp-net-sql-server-oop-concepts.html2026-10-29One hundred questions that come up in .NET developer interviews, grouped by topic, each with a short, accurate answer: OOP, C# language, ASP.NET Web Forms and MVC, ADO.NET, SQL Server, web basics and security.https://www.aspneto.com/best-asp-net-website-hosting-service-providers-you-must-use-to-host-your-website.htmlhttps://www.aspneto.com/best-asp-net-website-hosting-service-providers-you-must-use-to-host-your-website.html2026-10-28A vendor-neutral guide to hosting ASP.NET applications: Web Forms on Windows and IIS versus ASP.NET Core on Linux or Windows, shared hosting, VPS and cloud platforms, SQL Server options, the technical checklist, and how to test a host before migrating.https://www.aspneto.com/fade-in-and-fade-out-effect-using-css3-transition.htmlhttps://www.aspneto.com/fade-in-and-fade-out-effect-using-css3-transition.html2026-10-27Build fade-in and fade-out effects with the CSS transition property: opacity with visibility so hidden elements stop catching clicks, hover and class-toggle versions, timing functions, fading on page load with keyframes, and respecting prefers-reduced-motion.https://www.aspneto.com/tooltip-example-show-hide-hint-help-text-using-css3-transition.htmlhttps://www.aspneto.com/tooltip-example-show-hide-hint-help-text-using-css3-transition.html2026-10-26An accessible tooltip built with HTML and CSS3 transitions: positioning with absolute and transform, an arrow drawn with a pseudo-element, showing on hover and keyboard focus, aria-describedby, the Escape key, and using it next to ASP.NET form fields.https://www.aspneto.com/parser-error-when-deploying-asp-net-application.htmlhttps://www.aspneto.com/parser-error-when-deploying-asp-net-application.html2026-10-25How to read the ASP.NET 'Parser Error' and 'Configuration Error' pages after a deployment, and fix the usual causes: Could not load type, wrong CodeBehind vs CodeFile, missing bin assemblies, application not configured in IIS, allowDefinition=MachineToApplication, duplicate config sections and framework version mismatches.https://www.aspneto.com/unable-to-serialize-the-session-state-error-in-asp-net.htmlhttps://www.aspneto.com/unable-to-serialize-the-session-state-error-in-asp-net.html2026-10-24The 'Unable to serialize the session state. In StateServer and SQLServer mode…' error explained: what out-of-process session state requires, marking classes [Serializable], NonSerialized fields, objects that can never be serialized, and storing keys instead of heavy objects.https://www.aspneto.com/html-frameset-tag-with-example.htmlhttps://www.aspneto.com/html-frameset-tag-with-example.html2026-10-23How the HTML frameset and frame elements divided a browser window, a complete working example with rows, cols, name and target, why frameset is obsolete in HTML5, and the modern replacements: iframe, CSS grid layouts and server-side includes or master pages.https://www.aspneto.com/gridview-inline-add-insert-edit-update-delete-data-in-asp-net-c-vb.htmlhttps://www.aspneto.com/gridview-inline-add-insert-edit-update-delete-data-in-asp-net-c-vb.html2026-10-22A complete Web Forms example that edits SQL Server data directly in a GridView: binding, edit and cancel, updating with parameters, deleting with confirmation, and adding new rows through the footer row, with the events explained in order.https://www.aspneto.com/add-insert-edit-update-delete-show-gridview-data-in-asp-net-c-vb.htmlhttps://www.aspneto.com/add-insert-edit-update-delete-show-gridview-data-in-asp-net-c-vb.html2026-10-21A simple CRUD page in ASP.NET Web Forms: a form above a GridView adds records, a Select button loads a row into the form for editing, Update and Delete work by primary key, all with parameterised ADO.NET commands.https://www.aspneto.com/asp-net-dropdownlist-country-state-city-cascading-without-page-refresh.htmlhttps://www.aspneto.com/asp-net-dropdownlist-country-state-city-cascading-without-page-refresh.html2026-10-20Build dependent Country, State and City DropDownLists in ASP.NET Web Forms backed by SQL Server: AutoPostBack and SelectedIndexChanged, resetting child lists, then wrapping the lists in an UpdatePanel so only the lists refresh, with notes on event validation and view state.https://www.aspneto.com/asp-net-querystring-url-example-to-pass-multiple-parameters-using-c-vb-net.htmlhttps://www.aspneto.com/asp-net-querystring-url-example-to-pass-multiple-parameters-using-c-vb-net.html2026-10-19Build URLs with several query string parameters in ASP.NET Web Forms, encode values correctly with UrlEncode or HttpUtility.ParseQueryString, read and validate them with Request.QueryString, handle repeated keys, and avoid putting sensitive data in the URL.https://www.aspneto.com/oop-concepts-object-oriented-programming-concepts-with-examples.htmlhttps://www.aspneto.com/oop-concepts-object-oriented-programming-concepts-with-examples.html2026-10-18Object-oriented programming explained with one running C# example: classes and objects, encapsulation with properties, inheritance and constructors, virtual and override, abstract classes and interfaces, plus composition and the mistakes interviewers ask about.https://www.aspneto.com/how-to-send-test-mail-using-gmail-smtp-settings-in-asp-net-c-vb-net.htmlhttps://www.aspneto.com/how-to-send-test-mail-using-gmail-smtp-settings-in-asp-net-c-vb-net.html2026-10-17Send mail from an ASP.NET Web Forms page with SmtpClient and Gmail: smtp.gmail.com on port 587 with STARTTLS, app passwords now that Google no longer accepts plain passwords from apps, web.config mailSettings, TLS 1.2, attachments, common errors, and why to use a transactional service in production.https://www.aspneto.com/export-gridview-data-to-word-excel-text-pdf-file-asp-net-c-vb.htmlhttps://www.aspneto.com/export-gridview-data-to-word-excel-text-pdf-file-asp-net-c-vb.html2026-10-16Export the contents of an ASP.NET GridView: real .xlsx files with ClosedXML, CSV text with proper escaping, the old HTML-as-Excel/Word trick and its warning, PDF with an open-source library, and the VerifyRenderingInServerForm error explained.https://www.aspneto.com/how-to-upload-and-download-files-from-server-folder-in-asp-net.htmlhttps://www.aspneto.com/how-to-upload-and-download-files-from-server-folder-in-asp-net.html2026-10-15A safe file upload and download page in ASP.NET Web Forms: the FileUpload control, size limits in maxRequestLength and maxAllowedContentLength, generated file names, extension allow-lists, storage outside the web root, listing files and streaming them back with the right headers.