查询 Neo4j 并在 WPF 应用程序中使用 Net Driver 返回找到的节点

Question

I like to search in my neo4j db with a string and get all Nodes as results back to handle them later in an AutosuggestBox.

First throw was to bring up a connection and query then the db to return my Nodes.

Now Im having trouble to return each found Node with its attribute called Name if its match, im always getting strange results in my messagebaox where I try to check my returned Nodes:

        private static async Task<List<string>> GetSuggestionsFromNeoAsync(string currentInput) {

            IDriver driver = GraphDatabase.Driver("bolt://localhost:7687", AuthTokens.Basic("neo4j", "neo4j"));
            IAsyncSession session = driver.AsyncSession(o => o.WithDatabase("neo4j"));

            var query2Neo = "Match (p:Person { Name:'" + currentInput + "'}) RETURN p.samAccountName as name";

            IResultCursor cursor = await session.RunAsync(query2Neo);
            List<string> people = await cursor.ToListAsync(record => record["Name"].As<string>());

            await cursor.ConsumeAsync();

            await driver.CloseAsync();
            return people;
    }

Ive tryed to setup that Query to get Reults like from: https://github.com/neo4j/neo4j-dotnet-driver But most exmaples are for neo4j v3 with the Client.

thank you and best regards

update with working code:

        private static async Task ShowResultsAsync()
    {
        var found = await GetSuggestionsFromNeoAsync("Name");
        if (found.Count > 0)
        {
            //enumerate the inner list
            foreach (var item in found)
            {
                //output the actual item
                MessageBox.Show("Person found Entry: " + item);
            }
        }
        else {
            MessageBox.Show("Person not found");

        }

    }

Answer 1

GetSuggestionsFromNeoAsync is an asynchronous method. This mean that it will return when it hits an await and execute the remainder of the method when the Task being awaited has completed.

So when you call GetSuggestionsFromNeoAsync from your showREsults method, it runs synchronously until the IResultCursor cursor = await session.RunAsync(query2Neo) line and then returns, whereupon the MessageBox is shown. Please refer to the docs for more information about what happens in an async method.

If you want to display the MessageBox when the GetSuggestionsFromNeoAsync has completed, you should await the async method. For you to be able to do this, you need to add the async keyword to the signature of the showREsults method. You should also change its return type to Task and add the *Async suffix to its name:

private static async Task ShowResultsAsync()
{
    var found = await GetSuggestionsFromNeoAsync("Name");
    MessageBox.Show("Person found Entry: " + found.Name);
}