It's very useful to store control or page properties in ViewState. For example, you have ArticleId which comes from QueryString. You need to verify QueryString parameters format, make sure that this not a hack attemp. If it is in correct format, then make sure that article exists in database and etc. After postback you need to do this all over again. However you can store verified ArticleId in ViewState, so after postback you don't need to do verification all over again.
I used to store c# property in ViewState as follow:
public int AritcleId
{
get { return ViewState["AritcleId"] != null ? (int)ViewState["AritcleId"] : 0; }
set { ViewState["AritcleId"] = value; }
}
I even created a snippet for this. I knew about ?? c# operator, but never really used it. However ViewState property is a classic example for null-coalescing operator. Code above can be rewritten like this:
public int AritcleId
{
get { return (int)(ViewState["AritcleId"] ?? 0); }
set { ViewState["AritcleId"] = value; }
}
And here is a code snippet:
<?xml version="1.0" encoding="utf-8"?>
<CodeSnippets xmlns="http://schemas.microsoft.com/VisualStudio/2005/CodeSnippet">
<CodeSnippet Format="1.0.0">
<Header>
<Keywords>
<Keyword>propv</Keyword>
</Keywords>
<SnippetTypes>
<SnippetType>Expansion</SnippetType>
</SnippetTypes>
<Title>SnippetFile1</Title>
<Author>Viktar</Author>
<Description>
</Description>
<HelpUrl>
</HelpUrl>
<Shortcut>propv</Shortcut>
</Header>
<Snippet>
<Declarations>
<Literal Editable="true">
<ID>MyProperty</ID>
<ToolTip>Property Name</ToolTip>
<Default>MyProperty</Default>
<Function>
</Function>
</Literal>
<Literal Editable="true">
<ID>int</ID>
<ToolTip>Type</ToolTip>
<Default>int</Default>
<Function>
</Function>
</Literal>
<Literal Editable="true">
<ID>DefaultValue</ID>
<ToolTip>DefaultValue</ToolTip>
<Default>0</Default>
<Function>
</Function>
</Literal>
</Declarations>
<Code Language="csharp"><![CDATA[public $int$ $MyProperty$
{
get { return ($int$)(ViewState["$MyProperty$"] ?? $DefaultValue$); }
set { ViewState["$MyProperty$"] = value; }
}
]]></Code>
</Snippet>
</CodeSnippet>
</CodeSnippets>
You can create, change and manage code snippets using Snippet Designer. Don't forget to encrypt your ViewState as described in Encrypt ViewState in ASP.NET MSDN article.
