Compare a full dataset with a field (textbox)

Hi,

Using an expression, is there a way to compare a full dataset (all values within the dataset) to a field (a textbox)?

Currently I can get it to compare the textbox with the first value in the dataset, but not the other values.

My expression is as follows:

=IIF(Fields!Vehicle_Reg.Value LIKE ReportItems!Textbox81.Value, "Yes", "No")