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c#xamldata-binding
Tom Jerry
Tom Jerry

Reputation: 49

Does XAML binding support indexed properties?

I have a couple of textboxes binded with a Dictionary

<TextBox Text="{Binding Path=MyField[NotDefinedIndex], Mode=TwoWay}"></TextBox>

and it throws a "cannot connect to index" exception if I try to use a index not defined in the data context. Is there a way to catch this error, define the index (MyFileld["NotDefinedIndex"] = string.Empty) and then complete the binding?

Is there any way to bind on indexed properties in .NET Framework?

Upvotes: 1

Views: 1189

Answers (1)

Adi Lester
Adi Lester

Reputation: 25201

Hiding a binding error when you're binding to an undefined index is probably not a very good idea; however, it's possible to define a property that will access the dictionary and return string.Empty if the value doesn't exist, so you won't get a binding error. For example, in your view model:

public Dictionary<string, string> MyField { get; set; }

public string this[string key]
{
    get
    {
        string result;
        if (MyField.TryGetValue(key, out result))
        {
            return result;
        }

        return string.Empty;
    }
}

Then in XAML:

<TextBox Text="{Binding Path=[NotDefinedIndex], Mode=TwoWay}"></TextBox>

Upvotes: 1

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