How to pass objects between Pages in Blazor

Regarding more complex objects it is good to use StateContainer (in memory solution).

Register your StateContainer in MauiProgram.cs like:

builder.Services.AddScoped<StateContainer>(); 

where StateContainer.cs contains:

public readonly Dictionary<int, object> ObjectTunnel = new(); 

then just as an example I will create ComplexObject.cs where

public class ComplexObject { public int Count = 0; public string Color = string.Empty; } 

then when you have pages e.g. Index.razor and Counter.razor and you would like to send ComplexObject from one the the other, then in Index.razor inject StateContainer

and call something like:

public void OpenCounterWithData() { var data = new ComplexObject{Count = 3, Color="red"} _stateContainer.ObjectTunnel.Add(data.GetHashCode(), data) _navigationManager.Navigate($"counter/{data.GetHashCode()}") } 

and In Counter.razor you specify page like:

@page "/counter/{SetHashCode:int}" 

and Input parameter:

[Parameter] public int SetHashCode { get; set; } 

and e.g. in OnInitialized you can extract the value from StateContainer like:

protected override void OnInitialized() { var data = (ComplexObject) _stateContainer.ObjectTunnel[SetHashCode]; } 

after that you should also remove the object from the ObjectTunnel. This is basically the whole flow.

Optimizations:

• I have created a few extension methods to optimize the flow

StateContainerExtensions.cs

public static class StateContainerExtensions { public static int AddRoutingObjectParameter(this StateContainer stateContainer, object value) { stateContainer.ObjectTunnel[value.GetHashCode()] = value; return value.GetHashCode(); } public static T GetRoutingObjectParameter<T>(this StateContainer stateContainer, int hashCode) { return (T) stateContainer.ObjectTunnel.PopValue(hashCode); } } 

and DictionaryExtensions.cs

public static class DictionaryExtensions { public static TValue PopValue<TKey, TValue>(this Dictionary<TKey, TValue> dictionary, TKey keyName) where TKey : notnull { var value = dictionary[keyName]; dictionary.Remove(keyName); return value; } } 

With those extension methods you can instead

_stateContainer.ObjectTunnel.Add(data.GetHashCode(), data) 

use just:

_stateContainer.AddRoutingObjectParameter(data); 

and instead:

var data = (ComplexObject) _stateContainer.ObjectTunnel[SetHashCode]; _stateContainer.ObjectTunnel.Remove(SetHashCode); 

use:

var data = _stateContainer.GetRoutingObjectParameter<ComplexObject>(SetHashCode);