CODEWITHSUNDEEP
c#design-patterns
Dan
Dan

Reputation: 139

Need suggestions with c# design patterns

I have just started to learn about design patterns in C#.

I have two ComboBox and I need to change the content of the second ComboBox when the first ComboBox selected item is changed. Instead of using Switch statement, I'm not able to apply a design pattern here (factory design pattern I assume - from what I read so far).

class SomeClass
{
    private const string CONST_LANG_1 = "LANGUAGE_1";
    private const string CONST_LANG_2 = "LANGUAGE_2";
    private const string CONST_LANG_3 = "LANGUAGE_3";
    private const string CONST_LANG_4 = "LANGUAGE_4";
    // ...

    private const string CONST_LANG_1_SPK_1 = "SPEAKER_1_1";
    private const string CONST_LANG_1_SPK_2 = "SPEAKER_1_2";
    private const string CONST_LANG_2_SPK_1 = "SPEAKER_2_1";
    private const string CONST_LANG_2_SPK_2 = "SPEAKER_2_2";
    private const string CONST_LANG_3_SPK_1 = "SPEAKER_3_1";
    private const string CONST_LANG_3_SPK_2 = "SPEAKER_3_2";
    private const string CONST_LANG_4_SPK_1 = "SPEAKER_4_1";
    private const string CONST_LANG_4_SPK_2 = "SPEAKER_4_2";
    // ...

    private void cmbSelectLanguageDEMO_SelectedIndexChanged(object sender, EventArgs e)
    {
        switch( cmbSelectLanguageDEMO.SelectedIndex )
        {
            case 0: // CONST_LANG_1 -> Populate cmbSelectSpeakerDEMO
                break;

            case 1: // CONST_LANG_2 -> Populate cmbSelectSpeakerDEMO
                break;

            // ...
        }
    }
}

Can someone help me to apply a design pattern here? I really want to learn how to implement a design pattern on my project.

Any help will be appreciated!

Upvotes: 0

Views: 201

Answers (3)

ashish
ashish

Reputation: 2348

Not sure if the response is late.Maybe it is useful to somebody looking for similar solution. I feel the observer pattern might be what you are looking for.If you have an object whose state change should be notified to other objects then you use observer pattern.Here is a brief overview Observer design pattern.

Upvotes: 0

Nghia Bui
Nghia Bui

Reputation: 3784

I don't have a name for my suggestion design. But here is the best design I can think at the moment for you :)

interface Lang {
    void List<String> speakers();
}

class Lang1 : Lang {
    public override void List<String> speakers() {
        return ...;
    }
}

class Lang2 : Lang {
    public override void List<String> speakers() {
        return ...;
    }
}

List<Lang> langs = new List<>();
int idx = 0;
langs[idx++] = new Lang1();
langs[idx++] = new Lang2();

private void cmbSelectLanguageDEMO_SelectedIndexChanged(object sender, EventArgs e) {
    cmbSelectSpeakerDEMO.Items.AddRange( langs[cmbSelectLanguageDEMO.SelectedIndex].speakers() );
}

Upvotes: 2

serhiyb
serhiyb

Reputation: 4833

Have a look at strategy pattern https://en.wikipedia.org/wiki/Strategy_pattern

    private void cmbSelectLanguageDEMO_SelectedIndexChanged(object sender, EventArgs e)
    {
        Action[] selectLanguageStrategies = {LoadLang1, LoadLang2 };
        selectLanguageStrategies[cmbSelectLanguageDEMO.SelectedIndex]();
    }

    private void LoadLang1()
    {
        // CONST_LANG_1 -> Populate cmbSelectSpeakerDEMO
    }

    private void LoadLang2()
    {
        // CONST_LANG_2 -> Populate cmbSelectSpeakerDEMO
    }

Upvotes: 1

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