CRUD Operation using Web API and Windows Application

╰+攻爆jí腚メ 2022-08-06 06:30 63阅读 0赞

原文：[http://www.dotnetfunda.com/articles/show/2341/crud-operation-using-web-api-and-windows-application][http_www.dotnetfunda.com_articles_show_2341_crud-operation-using-web-api-and-windows-application]

## Introduction ##

In this article we will perform a basic CRUD operation using Web API and Windows Application

## Straight to Experiment ##

Fire up visual studio and choose "ASP.NET MVC 4 Web Application"

![Niladri.Biswas_7216_1.png][]

Next choose "Web API" and let the view engine be "Razor".Click "OK"

![Niladri.Biswas_8974_2.png][]

Add an Product Model (Product.cs) in the Models Folder

public class Product
    {
    	public int Id { get; set; }
    	public string Name { get; set; }
    	public string Category { get; set; }
    	public decimal Price { get; set; }
    }

Add an Interface IProductRepository.cs as under

interface IProductRepository
    {
    	IEnumerable GetAll();
    	Product Get(int id);
    	Product Add(Product item);
    	bool Update(Product item);
    	bool Delete(int id);
    }

Add a concrete ProductRepository.cs as under

public class ProductRepository : IProductRepository
    {
    	private List<Product> products = new List<Product>();
    	private int _nextId = 1;
    
    	public ProductRepository()
    	{           
    		Add(new Product { Name = "Floppy Disk", Category = "Hardware/Electronics", Price = 20.10M });            
    		Add(new Product { Name = "BMW", Category = "Car", Price = 3400000 });
    	}
    
    	public IEnumerable<Product> GetAll()
    	{           
    		return products;
    	}
    
    	public Product Get(int id)
    	{           
    		return products.Find(p => p.Id == id);
    	}
    
    	public Product Add(Product item)
    	{
    		item.Id = _nextId++;
    		products.Add(item);
    
    		return item;
    	}
    
    	public bool Update(Product item)
    	{
    		int index = products.FindIndex(p => p.Id == item.Id);           
    		products.RemoveAt(index);
    		products.Insert(index, item);
    		return true;
    	}
    
    	public bool Delete(int id)
    	{ 
    		products.RemoveAll(p => p.Id == id);
    		return true;
    	}
    }

Run the application

Now create a windows application and make a UI screen as under

![Niladri.Biswas_1025_3.png][]

For obtaining all the product, let us write the below code

private async void GetAllProducts() 
    { 
    	using (var client = new HttpClient())             
    	{
    		using (var response = await client.GetAsync(URI))
    		{                     
    			if (response.IsSuccessStatusCode) 
    			{                         
    				var productJsonString = await response.Content.ReadAsStringAsync();
    
    				dataGridView1.DataSource = JsonConvert.DeserializeObject<Product[]>(productJsonString).ToList();                       
    
    			}
    		}             
    	} 
    }

First of all we are creating an instance of the HttpClient. Then by using the "GetAsync" we are sending a GET request to the specified Uri as an asynchronous operation.

By using the "ReadAsStringAsync" method, we are writing the HTTP content to a string as an asynchronous operation.

The JsonConvert.DeserializeObject will convert the JSon string to the specified dotnet type.For this to use we need to download the [JSON.net][] library.And then add the "Newtonsoft.Json.dll" specific to the dotnet version.

Finally we are binding the result to the grid

![Niladri.Biswas_2782_4.png][]

For inserting a product, let us write the below code

private async void AddProduct()
    {           
    	Product p = new Product();
    	p.Id = 3;
    	p.Name = "Rolex";
    	p.Category = "Watch";
    	p.Price = 1299936;
    	using (var client = new HttpClient())
    	{
    		var serializedProduct = JsonConvert.SerializeObject(p);
    		var content = new StringContent(serializedProduct, Encoding.UTF8, "application/json");
    		var result = await client.PostAsync(URI, content);
    	}
    	GetAllProducts();                       
    }

First of all we are creating the product object and adding a product to it.Then serializing the product to the JSon string by using the "JsonConvert.SerializeObject" method.

Finally we are using the "PostAsync" method for sending a POST request to the specified Uri as an asynchronous operation.

And invoking the "GetAllProducts()" to show the new collection.

![Niladri.Biswas_6396_5.png][]

The update method implementation is as under

private async void UpdateProduct()
    {
    	Product p = new Product();
    	p.Id = 3;
    	p.Name = "Rolex";
    	p.Category = "Watch";
    	p.Price = 1400000; //changed the price
    
    	using (var client = new HttpClient())
    	{
    		var serializedProduct = JsonConvert.SerializeObject(p);
    		var content = new StringContent(serializedProduct, Encoding.UTF8, "application/json");
    		var result = await client.PutAsync(String.Format("{0}/{1}", URI, p.Id), content);
    	}
    	GetAllProducts(); 
    }

The implementation is very similar to the Insert methid except that we are using "PutAsync" that will send a PUT request to the specified Uri as an asynchronous operation.

![Niladri.Biswas_9618_6.png][]

And finally comes the Delete method whose implementation is as under

private async void DeleteProduct()
    {
    	using (var client = new HttpClient())
    	{                
    		var result = await client.DeleteAsync(String.Format("{0}/{1}", URI, 3));
    	}            
    	GetAllProducts();
    }

We are passing the id(which is 3 in this case) to the "DeleteAsync" method that will send a DELETE request to the specified Uri as an asynchronous operation.

![Niladri.Biswas_0497_7.png][]

## Conclusion ##

Hope this will be helpful.Thanks for reading.Zipped file is attached herewith.

[http_www.dotnetfunda.com_articles_show_2341_crud-operation-using-web-api-and-windows-application]: http://www.dotnetfunda.com/articles/show/2341/crud-operation-using-web-api-and-windows-application
[Niladri.Biswas_7216_1.png]: /images/20220806/18a5aabc933b436c94146db4562e1c5c.png
[Niladri.Biswas_8974_2.png]: /images/20220806/f8f295935d7d4469920bcbbecb037ba4.png
[Niladri.Biswas_1025_3.png]: /images/20220806/9d0019dbd5c04fd4a1ed25acdbaf929d.png
[JSON.net]: http://james.newtonking.com/projects/json-net.aspx
[Niladri.Biswas_2782_4.png]: /images/20220806/170e24fc87b8466b9e4043b935328736.png
[Niladri.Biswas_6396_5.png]: /images/20220806/c7b87736dc344c00ac58d9012d029b64.png
[Niladri.Biswas_9618_6.png]: /images/20220806/fc8783edc8b74397befb31d48af20f2b.png
[Niladri.Biswas_0497_7.png]: /images/20220806/c18d487bae9c41988ae2d99437e25d31.png