MS Access - If Statement with combo box and textbox

Question

I have a combo list box that has 4 values (a,b,c,d). I have a textbox also. I want the textbox to update based on the value selected from the combobox. For example, the textbox has a default value of text. I want to put an if statement somewhere that says if combobox value = b then make the text in the textbox "Yes" else make it "No". I don't know what the if statement should be or where it should go. I'd like to do this without coding.

Answer 1

用作文本框的ControlSource：

=IIf([NameOfYourCombobox]="b","Yes","No")