How to access WPF datagrid Template Column?

I'm using WPF 4.0... I created a custom control like decimal textbox... I had inserted that decimal textbox in datagrid template column... Now my problem is that,

How to access that template column or that decimal tex开发者_开发技巧tbox in Code behind( C#)????

Thanks in Advance

In xaml:

<DecimalTextbox x:Name="MyTextBox" />

In Code-behind:

MyTextBox.MyProperty