CODEWITHSUNDEEP
c#winforms
Winter
Winter

Reputation: 35

A switch expression and an operator error

I have two lines of code which are giving me errors: 

private void combobox1_SelectedIndexChanged(object sender, EventArgs e)
        {
    switch (combobox1.SelectedValue)
                {
                    case 0:
                        var item = items.Where(category => category.CategoryIndex == 0);

                        foreach (var i in item)
                        {
                            listbox.Items.Add(new Items { CategoryIndex = i.CategoryIndex, ItemDesc = i.ItemDesc, ItemName = i.ItemName });
                        }
                        break;


                    case 1:
                        item = items.Where(category => category.CategoryIndex == 1);

                        foreach (var i in item)
                        {
                            listbox.Items.Add(new Items { CategoryIndex = i.CategoryIndex, ItemDesc = i.ItemDesc, ItemName = i.ItemName });
                        }
                        break;

Heres the second : 

 private void listbox_SelectedIndexChanged(object sender, EventArgs e)
        {
            var item = items.Where(category => category.CategoryIndex == listbox.SelectedValue && (itemName => itemName.ItemName == listbox.SelectedItem.ToString()));

            listbox.Text = item.ItemName;
            desrciption_label.Text = item.ItemDesc;     
        }

The error in the first code is at 

switch (combobox.SelectedValue)

The error states that:

A switch expression or case label must be bool, char, string, integral, enum, or corresponding nullable type_

The error in the second code is at 

category.CategoryIndex == listbox.SelectedValue

This error states that:

Operator '==' cannot be applied to operands of type 'int' and 'object'

How to fix these?

NOTE: There is more a lot code to this, since it's so big I'm leaving it out but if the previous code is needed, please inform me of this

Upvotes: 0

Views: 150

Answers (3)

tjcertified
tjcertified

Reputation: 704

In both cases, you will need to cast that combobox.SelectedValue to something else, i.e.

int choice = (int)combobox.SelectedValue;

depending on whatever type of thing SelectedValue is.

This is because combobox.SelectedValue is an object, so you need to cast it to your data type. See here for details on ComboBox properties.

Upvotes: 3

Sami
Sami

Reputation: 2110

The errors are self-explanatory. The first comes from SelectedValue returning an Object, which is not allowed in a switch-statement. You should most likely use SelectedIndex.
Second means that you can't compare int with Object.
CategoryIndex is an int, and you can't compare it to SelectedValue, which is an object, like in the first case. Again using SelectedIndex should fix it.
If the SelectedValue is in fact the property you should be using (after databinding for example), cast the object to an int to get proper types (or parse).

Upvotes: 1

TheNorthWes
TheNorthWes

Reputation: 2739

[BrowsableAttribute(false)]
[BindableAttribute(true)]
public ***object*** SelectedValue { get; set; }`

See here for more.

You are passing in an object to the switch, but the cases are integers. You need to resolve that selected value to an integer. Perhaps a straight cast will work but I don't know what is in that combobox.

Upvotes: 1

Related Questions