此方法不接受此参数为null

本文关键字：null 参数 不接受 此方法 | 更新日期: 2023-09-27 18:29:22

我想为windows phone 7制作一个宠物护理游戏，但我遇到了问题，它告诉我我有一个null方法，但我不知道为什么我在游戏中有一个来自每个状态的枚举。

这是消息的图片：http://crystalnix.deviantart.com/art/XNa-Problem-396626207?ga_submit_new=10%253A1377747418

这是主文件。

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Input.Touch;
using Microsoft.Xna.Framework.Media;
using Mochi_Mochi_Pets_Life.Script.Screen;
namespace Mochi_Mochi_Pets_Life
{
public class MainFile : Microsoft.Xna.Framework.Game
{
    GraphicsDeviceManager graphics;
    SpriteBatch spriteBatch;
    ScreenStates screentState;
    Rectangle TouchS_Y_X;
    Logo logo;
    Menu0 menu;
    Choose_Pets choose_pets;
    ScreenStates.CurrentGameState GameState;
    public MainFile()
    {
        graphics = new GraphicsDeviceManager(this);
        Content.RootDirectory = "Content";
        Content.RootDirectory = "Script''Screen";
        choose_pets = new Choose_Pets();
        this.screentState = new ScreenStates();
        this.logo = new Logo(GraphicsDevice);
        this.menu = new Menu0();
        // Frame rate is 30 fps by default for Windows Phone.
        TargetElapsedTime = TimeSpan.FromTicks(333333);
        // Extend battery life under lock.
        InactiveSleepTime = TimeSpan.FromSeconds(1);
        GameState = ScreenStates.CurrentGameState.Logo;

    }

    protected override void Initialize()
    {
        choose_pets.Initialize_choosepets();
        // TODO: Add your initialization logic here
        base.Initialize();
    }

    protected override void LoadContent()
    {
        TouchS_Y_X = new Rectangle(0, 0, 1, 1);
        // Create a new SpriteBatch, which can be used to draw textures.
        spriteBatch = new SpriteBatch(GraphicsDevice);
        if (GameState == ScreenStates.CurrentGameState.Logo)
            this.logo.Load(this.Content, this.GraphicsDevice);
        if (GameState == ScreenStates.CurrentGameState.Menu)
            this.menu.Load_Menu(GraphicsDevice, Content);
        if (logo.FadeOut_logo == true)
            GameState = ScreenStates.CurrentGameState.Menu;
        if (GameState == ScreenStates.CurrentGameState.CharactersChooser)
        this.choose_pets.Load_ChoosePet(this.Content, this.GraphicsDevice);
        // TODO: use this.Content to load your game content here
    }

    protected override void UnloadContent()
    {
        // TODO: Unload any non ContentManager content here
        //this.logo.Unload_logo(Content);
    }

    protected override void Update(GameTime gameTime)
    {
        // Allows the game to exit
        if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
            this.Exit();
                    if (GameState == ScreenStates.CurrentGameState.Logo)
                logo.Update_logo(gameTime);

                    if (GameState == ScreenStates.CurrentGameState.CharactersChooser)
                    choose_pets.Update_petchoose(gameTime);
        // TODO: Add your update logic here
        base.Update(gameTime);
    }

    protected override void Draw(GameTime gameTime)
    {
        GraphicsDevice.Clear(Color.Black);
        spriteBatch.Begin();
                    if (GameState == ScreenStates.CurrentGameState.Logo)
                        logo.Draw(spriteBatch);
                    if (logo.FadeOut_logo == true)
                        menu.Draw_Menu(spriteBatch);
                    if (GameState == ScreenStates.CurrentGameState.CharactersChooser)
                        choose_pets.Draw_petChoose(spriteBatch);
        spriteBatch.End();
        base.Draw(gameTime);
    }
}
}

这个菜单给了我的问题

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using Microsoft.Xna.Framework.Graphics;
    using Microsoft.Xna.Framework;
    using Microsoft.Xna.Framework.Content;
    namespace Mochi_Mochi_Pets_Life
    {
class Menu0
{
    Texture2D Text2D_Background;
    Rectangle Rec_Background;
    Texture2D ButtonText2DPlay;
    Rectangle ButtonRecPlay;

    public void Load_Menu(GraphicsDevice Graphics_Menu, ContentManager Content_Menu)
    {
        Content_Menu.RootDirectory = "Content"; 
        Text2D_Background = Content_Menu.Load<Texture2D>("UI''MenuBack");
        Rec_Background = new Rectangle(0, 0, Graphics_Menu.Viewport.Width,                 Graphics_Menu.Viewport.Height);
        ButtonText2DPlay = Content_Menu.Load<Texture2D>("UI''Buttons''New Games");
        ButtonRecPlay = new Rectangle(Graphics_Menu.Viewport.Width, 400, 150, 40);
    }

    public void Draw_Menu(SpriteBatch Spritebatch_Menu)
    {
        Spritebatch_Menu.Draw(Text2D_Background, Rec_Background, Color.White);
        Spritebatch_Menu.Draw(ButtonText2DPlay, ButtonRecPlay, Color.White);
    }
}
    }

好吧，这是因为当我的标志褪色＝＝true时，游戏状态跳转到主马努，但它永远不会发生总是错误，我会感谢你的帮助。。

此方法不接受此参数为null

从未调用Loading_Menu，因此纹理Text2D_Background始终为空

你应该意识到LoadContent只在游戏初始化时调用，所以比较游戏状态是没有用的，因为只会加载Logo内容。

作为解决方案，您可以在初始化时加载所有内容，也可以在游戏状态更改时加载，如果在之前没有加载所需内容

我认为您的Text2D_Background为null，这是因为您从不调用Load_Menu。在LoadContent中选中gameState，它将返回false。

if (GameState == ScreenStates.CurrentGameState.Menu)

LoadContent只调用一次，我不明白为什么要检查gameState的值。

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