Author: ErcanOPAK

ASP.Net MVC / ASP.Net WebForms / JavaScript

How to disable ASP.Net button after click to prevent double clicking

- - ErcanOPAK comment on How to disable ASP.Net button after click to prevent double clicking

Let’s say you have 2 buttons on your web page. <form id=”form1″ runat=”server”> <asp:Button ID=”Button1″ runat=”server” Text=”Button1″ OnClick=”Button1_Clicked” /> <asp:Button ID=”Button2″ runat=”server” Text=”Button2″ /> </form> Scenario 1: Disabling the specific button <script type=”text/javascript”> function DisableButton() { document.getElementById(“<%=Button1.ClientID %>”).disabled = true; } window.onbeforeunload = DisableButton; </script> The DisableButton JavaScript function is used for disabling specific Button when Clicked. […]

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C# / LINQ

What is the difference between Select and SelectMany in Linq

- - ErcanOPAK comment on What is the difference between Select and SelectMany in Linq

The formal description for SelectMany() is: Projects each element of a sequence to an IEnumerable and flattens the resulting sequences into one sequence. SelectMany() flattens the resulting sequences into one sequence and invokes a result selector function on each element. The main difference is the result of each method while SelectMany() returns flattened results; Select() […]

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LINQ

Differences between FirstOrDefault and SingleOrDefault in LINQ

- - ErcanOPAK comment on Differences between FirstOrDefault and SingleOrDefault in LINQ

Whenever you use SingleOrDefault, you clearly state that the query should result in at most a single result. On the other hand, when FirstOrDefault is used, the query can return any amount of results but you state that you only want the first one. If your result set returns 0 records: Single throws an exception First throws an exception SingleOrDefault returns the default […]

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SQL

How to reset identity seed after deleting records in SQL

- - ErcanOPAK comment on How to reset identity seed after deleting records in SQL

The DBCC CHECKIDENT management command is used to reset the identity counter. The command syntax is: DBCC CHECKIDENT (table_name [, { NORESEED | { RESEED [, new_reseed_value ]}}]) [ WITH NO_INFOMSGS ] Example: DBCC CHECKIDENT (‘[TestTable]’, RESEED, 0); IMPORTANT: The following example forces the current identity value in the AddressTypeID column in the AddressType table to a value […]

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C#

The Null Conditional Operator in C# (?.)

- - ErcanOPAK comment on The Null Conditional Operator in C# (?.)

The null conditional operator (?.) is colloquially referred to as the “Elvis operator” because of its resemblance to a pair of dark eyes under a large quiff of hair. The null conditional is a form of a member access operator (the .). Here’s a simplified explanation for the null conditional operator: The expression A?.B evaluates to B if the left operand (A) […]

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C#

The Null-Coalescing Operators in C# (?? and ??=)

- - ErcanOPAK comment on The Null-Coalescing Operators in C# (?? and ??=)

The null-coalescing operator ?? returns the value of its left-hand operand if it isn’t null; otherwise, it evaluates the right-hand operand and returns its result. The ?? operator doesn’t evaluate its right-hand operand if the left-hand operand evaluates to non-null. int? myValue = null; int result = myValue ?? -1; //result = -1; Syntax: p ?? q Here, p is […]

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SQL

How to create a single string from multiple rows in T-SQL and MySQL

- - ErcanOPAK comment on How to create a single string from multiple rows in T-SQL and MySQL

To create a single string from multiple rows in MySQL, you can use the GROUP_CONCAT function. This function allows you to concatenate values from multiple rows into a single string, separated by a specified delimiter. Here is an example of how you can use this function: SELECT GROUP_CONCAT(column_name ORDER BY column_name ASC SEPARATOR ‘,’) FROM […]

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ASP.Net MVC / ASP.Net WebForms / CSS / HTML

How to align inconsistently sized logos with CSS

- - ErcanOPAK comment on How to align inconsistently sized logos with CSS

These 3 lines will save you (fit, line up, remove background): aspect-ratio: 3/2; object-fit: contain; mix-blend-mode:color-burn; Let’s see how you can use that: In the body section, we have a div with the “photoDiv” class. <div class=”photoDiv”> <img src=”1.png”> <img src=”2.png”> <img src=”3.png”> <img src=”4.png”> <img src=”5.png”> </div> And here is the magical CSS: <style> […]

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SQL

SQL Tip: “NOCOUNT” should be activated on “PROCEDURE” and “TRIGGER” definitions

- - ErcanOPAK comment on SQL Tip: “NOCOUNT” should be activated on “PROCEDURE” and “TRIGGER” definitions

NOCOUNT is by default deactivated (OFF) at the server level. It means by default, the server will send to the client the number of rows affected by the SQL query executed which is, in most cases, useless because no one will read this information. Deactivating this feature will save some network traffic and improve the […]

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SQL

SQL Tip: “NULL” should not be compared directly

- - ErcanOPAK comment on SQL Tip: “NULL” should not be compared directly

“NULL” is never equal to anything, even itself. Therefore comparisons using equality operators will always return False, even when the value actually IS NULL. For that reason, comparison operators should never be used to make comparisons with NULL; IS NULL and IS NOT NULL should be used instead. Bad example: UPDATE books SET title = ‘unknown’ WHERE title = NULL — Noncompliant […]

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C#

What is the difference between IQueryable and IEnumerable?

- - ErcanOPAK comment on What is the difference between IQueryable and IEnumerable?

That StackOverflow answer so far is the best one I have ever seen: This is an excellent video on youtube which demonstrates how these interfaces differ, worth a watch. Below goes a long descriptive answer to it. The first important point to remember is IQueryable interface inherits from IEnumerable, so whatever IEnumerable can do, IQueryable can also do. There are many differences […]

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ASP.Net WebForms

How to get output return value from SqlDataSource in WebForms

- - ErcanOPAK comment on How to get output return value from SqlDataSource in WebForms

When returning a string from a stored procedure as a return parameter, we must set it to a non-null value before the stored proc is called – even if it’s an output-only parameter. So we’ll need to make your parameter have a direction of InputOutput and set a default value: <asp:Parameter Name=”MyReturnParameter” Type=”String” Direction=”InputOutput” DefaultValue=”A […]

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ASP.Net MVC / ASP.Net WebForms / HTML / JavaScript

How to use client-side function on checkbox or any asp.net component

- - ErcanOPAK comment on How to use client-side function on checkbox or any asp.net component

Here is the Asp part: <label for=”chkCondition”> <asp:CheckBox ID=”chkCondition” Text=”Should i show the div?” runat=”server” onclick=”ShowHideDiv(this)” /> </label> <hr /> <div id=”divToShowOrHide” style=”display: none”> this div will be shown regarding the checkbox checked status. <asp:TextBox ID=”myTextBox” runat=”server” /> </div> And here is the Javascript part: <script type=”text/javascript”> function ShowHideDiv(chkCondition) { var divToShowOrHide = document.getElementById(“divToShowOrHide”); divToShowOrHide.style.display […]

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ASP.Net MVC / ASP.Net WebForms / CSS / HTML

How to apply two classes to a single element in CSS

- - ErcanOPAK comment on How to apply two classes to a single element in CSS

Let’s say you want to use 2 or more classes for a div. Then you should use these classes inside the class attribute, separated by whitespace: <div class=”myFirstClass mySecondClass”></div> To target elements that contain all of the specified classes, use this CSS selector (no space) in your CSS file: .myFirstClass.mySecondClass {}  

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ASP.Net WebForms / C# / Devexpress

How to create the ShowBlanksValue and ShowNonBlanksValue items in Devex Grid

- - ErcanOPAK comment on How to create the ShowBlanksValue and ShowNonBlanksValue items in Devex Grid

By design, GridViewDataComboBoxColumn does not render (Blank) and (NonBlank) items if the HeaderFilterMode property is set to CheckedList. However, you can add these items in the HeaderFilterFillItems event handler. Just call the FilterValue.CreateShowBlanksValue and FilterValue.CreateShowNonBlanksValue methods. <dx:ASPxGridView ID=”grid” runat=”server” AutoGenerateColumns=”False” DataSourceID=”dsCategories” KeyFieldName=”CategoryID” OnHeaderFilterFillItems=”grid_HeaderFilterFillItems”> <Columns> <dx:GridViewDataTextColumn FieldName=”CategoryID”> </dx:GridViewDataTextColumn> <dx:GridViewDataTextColumn FieldName=”Description”> </dx:GridViewDataTextColumn> <dx:GridViewDataComboBoxColumn FieldName=”CategoryNameNull” Caption=”Category Name”> <Settings HeaderFilterMode=”CheckedList” /> <PropertiesComboBox DataSourceID=”dsCategories” ValueField=”CategoryNameNull” TextField=”CategoryNameNull” /> </dx:GridViewDataComboBoxColumn> </Columns> […]

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SQL

How to get ‘n’th row in Sql Query with OFFSET FETCH NEXT and ROW_NUMBER()

- - ErcanOPAK comment on How to get ‘n’th row in Sql Query with OFFSET FETCH NEXT and ROW_NUMBER()

In SQL Server 2012+, you can use OFFSET…FETCH. The below query will help you to get 2nd row. But with little changes, you can get the ‘n’th row as well. SELECT <column(s)> FROM <table(s)> ORDER BY <sort column(s)> OFFSET 1 ROWS — Skip this number of rows FETCH NEXT 1 ROWS ONLY; — Return this […]

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