Select string value from database with sqlite

Question

I have a problem. I am trying to get a value (string) from my database. Here is the code I am calling to get the value:

public string SelectValueFromTableSettings(string name)
{
    string folder = System.Environment.GetFolderPath(System.Environment.SpecialFolder.Personal);
    try
    {
        using (var connection = new SQLiteConnection(System.IO.Path.Combine(folder, "Settings.db")))
        {
            return connection.Query<SettingDb>("SELECT Value FROM SettingDb WHERE Name=?", name).ToString();
        }
    }
    catch (SQLiteException ex)
    {
        Log.Info("SQLiteEx", ex.Message);
        return null;
    }
}

And here is the code to assign the value to a variable:

string SwitchValue = MainActivity.db.SelectValueFromTableSettings(mItems[position].Name);

I am supposed to get a value like Nick or Steve, but I get this as value:

System.Collections.Generic.List`1[CryptoCurrencies.SettingDb]

What am I doing wrong?

Instead of enumerating the results of connection.Query<SettingDb>("..."), you're calling ToString() on it. connection.Query<SettingDb>() returns List<SettingDb>. Because there's no sensible stringification of List<T>, it just has the default ToString() which returns GetType().FullName or whatever. Instead, loop through the list. — 15ee8f99-57ff-4f92-890c-b56153
– 15ee8f99-57ff-4f92-890c-b56153, Commented Jun 11, 2019 at 17:49
Loop through the list the query returns. See if there's anything in it. — 15ee8f99-57ff-4f92-890c-b56153
– 15ee8f99-57ff-4f92-890c-b56153, Commented Jun 11, 2019 at 17:51
when you call ToString() on Query result, you are getting the name of the result class which is a list of setting. Use FirstOrDefault() instead of ToString() to the first data in list and use SettingDb properties to get the desired result. — Khizar Iqbal
– Khizar Iqbal, Commented Jun 11, 2019 at 17:52

Bruno Caceiro · Accepted Answer · 2019-06-11 19:40:50Z

2

You are returning a list of objects.

connection.Query<SettingDb>("SELECT Value FROM SettingDb WHERE Name=?", name).FirstOrDefault().YourProperty.ToString();

Or, simply return the object:

public SettingDB SelectValueFromTableSettings(string name)
{
    string folder = System.Environment.GetFolderPath(System.Environment.SpecialFolder.Personal);
    try
    {
        using (var connection = new SQLiteConnection(System.IO.Path.Combine(folder, "Settings.db")))
        {
            return connection.Query<SettingDb>("SELECT Value FROM SettingDb WHERE Name=?", name).FirstOrDefault();
        }
    }
    catch (SQLiteException ex)
    {
        Log.Info("SQLiteEx", ex.Message);
        return null;
    }
}

And then acess to the desired property.

answered Jun 11, 2019 at 19:40

Bruno Caceiro

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1 Comment

A. Vreeswijk Over a year ago

Thanks, this helped me a lot

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