Operator '||' cannot be applied to operands of type 'object' and 'bool'

Question

I would like to do a comparison of :
ComboBox.SelectedItem which is of the object type to the string.Empty in combination with "||"

If I run with above command I get an error:

"Operator '||' cannot be applied to operands of type 'object' and 'bool' "

Code

if (comboBox2.SelectedItem || comboBox1.SelectedItem == string.Empty )

Antoine V · Answer 1 · 2018-09-28T09:30:01.870

3

Try this:

if ((comboBox1.SelectedItem?.Equals(string.Empty) ?? false)
    || (comboBox2.SelectedItem?.Equals(string.Empty) ?? false))

edited Sep 28 '18 at 09:30

answered Sep 28 '18 at 09:15

Antoine V

6,998
2
11
34

I need to check it for all the combobox from 1 to 10 in same if statement and I need a || operator – Parnal p Sep 28 '18 at 09:21
@Parnalp so what? – Antoine V Sep 28 '18 at 09:22
I could have simply written : string combox1 = comboBox1.SelectedItem as string; if(combox1 == string.Empty) Its the same what you did. – Parnal p Sep 28 '18 at 09:25
I think you should run it before posting, I am sorry but for ?? it shows the same error – Parnal p Sep 28 '18 at 09:38
@Parnalp I run it before posting. Recheck your code – Antoine V Sep 28 '18 at 09:39

Amy · Answer 2 · 2018-09-28T09:44:43.043

0

Try this

if((comboBox1.SelectedItem==null || comboBox1.SelectedItem == string.Empty) || (comboBox2.SelectedItem == null || comboBox2.SelectedItem == string.Empty))
{
     MessageBox.Show("Select Item!");
}

edited Sep 28 '18 at 09:44

answered Sep 28 '18 at 09:22

Amy

35
12

Now it should be fine – Amy Sep 28 '18 at 09:28
1

nope.. throws in the same error "Operator '||' cannot be applied to operands of type 'object' and 'bool' " – Parnal p Sep 28 '18 at 09:30
Okay wait i just try to implement i'll make you sure about it – Amy Sep 28 '18 at 09:32
Yeah, now it's fine you can Judge it now. – Amy Sep 28 '18 at 10:07

score 0 · Answer 3 · answered Sep 28 '18 at 09:52

You can't compare bool and object (selected item of a combo box) based on @ThierryV answer you can define an function like this for check your condition :

private bool CheckEmptyComboBox(ComboBox comboBox)
{
    return (comboBox.SelectedItem==string.Empty ?? false)
}

and then should use this function in your if statement condition:

if( CheckEmptyComboBox(comboBox1) || CheckEmptyComboBox(comboBox2) || CheckEmptyComboBox(comboBox3) ...)

also you can use a foreach statement to find all Combo boxes in a panel or group box

Operator '||' cannot be applied to operands of type 'object' and 'bool'

3 Answers3