Cannot implicitly convert type 'Java.Lang.Object' to 'Android.Runtime.JavaDictionary<string, string>

问题

I am applying Google Places Api on my app and converting the Java to C# code. But when I am getting the nearby places in the list, I got this error:

Cannot implicitly convert type 'Java.Lang.Object' to 'Android.Runtime.JavaDictionary'. An explicit conversion exists (are you missing a cast?)

private void showNearbyPlaces(JavaList<JavaDictionary<string, string>> placeList)
    {
        for (int eachPlace = 0; eachPlace < placeList.Size(); eachPlace++)
        {

            MarkerOptions markerOptions = new MarkerOptions();
            JavaDictionary<string, string> googlePlace = placeList.Get(eachPlace); /*This is the error*/
        }
    }

Screenshot of the code

Any know how to fix this? Thank you.

回答1:

You could use System.Collections.Generic.List instead of JavaList, for example :

using System.Linq;

...

private void showNearbyPlaces(List<JavaDictionary<string, string>> placeList)
{
    for (int eachPlace = 0; eachPlace < placeList.Count; eachPlace++)
    {
        JavaDictionary<string, string> googlePlace = placeList.ElementAt(eachPlace);
    }
}

回答2:

Try explicitly casting it:

JavaDictionary<string, string> googlePlace = (type)placeList.Get(eachPlace)

If that doesn't work, I'd suggest converting the placeList to a more primitive object (strings most likely), and then reconstructing it as a dictionary:

JavaDictionary<string, string> googlePlace = placeList.Get(eachPlace).ConvertToString();

public JavaDictionary<string, string> ConvertToString(this [placeListType] placeList)
{
    // Create a dictionary

    // foreach object in placeList
    // Get the first string and assign it
    // Get the second string and assign it
    // Create a new object with them as parameters
    // Add object to dictionary

    // Return dictionary
} 

回答3:

Use C# IDictionary instead like this,

IDictionary<string, string> placeList= new Dictionary<string, string>();
placeList.Add(new KeyValuePair<string, string>("your string", "your new string"));

来源：https://stackoverflow.com/questions/48161076/cannot-implicitly-convert-type-java-lang-object-to-android-runtime-javadictio