You can hide a TextBox in a RDLC using a visibility formula.
If you want to hide any textbox in RDLC, you can do this using the visibility formula as below.Right-click on the TextBox and select TextBox Properties. From the Properties window select Visibility and click on "Show or hide based on an expression".In the Expression window enter the Expression as you like ( iif(Fields!YouField.Value>0,false,true) )
Printing in C# Made Easy