Using stored procedures and views in Blazor 8 application

To use Entity Framework Core (EF Core) in Blazor Server or WebAssembly (Blazor WASM) apps to work with stored procedures and views in a SQL database, you follow these general steps:

1. Set Up Your Application

• Create a Blazor Server or WebAssembly project.
• Install the required NuGet packages for EF Core:

  dotnet add package Microsoft.EntityFrameworkCore.SqlServer
  dotnet add package Microsoft.EntityFrameworkCore.Tools
  

2. Create a Database Context

Define a DbContext that represents your database and includes DbSets for the views or models.

using Microsoft.EntityFrameworkCore;

public class AppDbContext : DbContext
{
    public AppDbContext(DbContextOptions options) : base(options) { }

    // Define DbSet for a view or entity
    public DbSet MyViewData { get; set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        // Map the view to a model
        modelBuilder.Entity().ToView("MyViewName");
    }
}

3. Define Your ViewModel

Create a model that matches the columns of the view or the result set of the stored procedure.

public class MyViewModel
{
    public int Id { get; set; }
    public string Name { get; set; }
    public decimal Value { get; set; }
}

4. Call Stored Procedures Using EF Core

EF Core allows direct execution of stored procedures with raw SQL queries.

Example Stored Procedure

CREATE PROCEDURE GetItemsByCategory
    @CategoryId INT
AS
BEGIN
    SELECT Id, Name, Value
    FROM Items
    WHERE CategoryId = @CategoryId
END

Executing the Stored Procedure in EF Core

using Microsoft.EntityFrameworkCore;

// Method in a service or repository
public async Task> GetItemsByCategory(int categoryId)
{
    return await _dbContext.MyViewData
        .FromSqlInterpolated($"EXEC GetItemsByCategory @CategoryId = {categoryId}")
        .ToListAsync();
}

5. Inject DbContext in Blazor Components

Configure DI in Program.cs:

builder.Services.AddDbContext(options =>
    options.UseSqlServer("YourConnectionString"));

Use the DbContext in a Blazor component to populate a form.

Example Component: FetchData.razor

@inject AppDbContext DbContext

Fetch Data


    Category 1
    Category 2


@if (items != null)
{
    
            @foreach (var item in items)
            {
                
            }
        

        

            

                
Id
                
Name
                
Value
            
        
        

                    
@item.Id
                    
@item.Name
                    
@item.Value
                
    
}

@code {
    private List items;

    private async Task LoadData(ChangeEventArgs e)
    {
        int categoryId = int.Parse(e.Value.ToString());
        items = await DbContext.MyViewData
            .FromSqlInterpolated($"EXEC GetItemsByCategory @CategoryId = {categoryId}")
            .ToListAsync();
    }
}

6. Use Custom Forms for Input

Create forms in Blazor to interact with the data.

Example Form

    
    

    
    

    Submit


@code {
    private MyViewModel newItem = new();

    private async Task HandleValidSubmit()
    {
        // Example of saving via EF Core
        var result = await DbContext.Database.ExecuteSqlInterpolatedAsync(
            $"EXEC SaveItem @Name = {newItem.Name}, @Value = {newItem.Value}");
        // Handle result
    }
}

Key Notes

1. Stored Procedures:

   • Use .FromSqlInterpolated or .FromSqlRaw to execute stored procedures.
   • Validate inputs to prevent SQL injection.

2. Views:

   • Use modelBuilder.Entity().ToView("ViewName") to map database views.

3. Error Handling:

   • Use try-catch to handle database errors.

4. Asynchronous Programming:

   • Always use async/await with EF Core to prevent blocking.

Let me know if you need further clarification or help with specific scenarios!

Hi Dan Slaby,

To use Entity Framework Core in Blazor 8 for working with stored procedures and views, you first need to set up your DbContext to include the necessary configurations. Here’s a step-by-step approach:

1. Install Required Packages: Ensure you have the necessary NuGet packages installed, such as Microsoft.EntityFrameworkCore.SqlServer and Microsoft.EntityFrameworkCore.Tools.

2. Define Your DbContext: Create a DbContext class that includes DbSet properties for your views and methods for executing stored procedures.

   public class ApplicationDbContext : DbContext
   {
       public ApplicationDbContext(DbContextOptions options) : base(options) { }
   
       public DbSet YourView { get; set; }
   
       public async Task> ExecuteStoredProcedureAsync(string param)
       {
           return await this.Set()
               .FromSqlRaw("EXEC YourStoredProcedure @param = {0}", param)
               .ToListAsync();
       }
   }
   

3. Inject DbContext in Blazor Component: In your Blazor component, inject the DbContext and call the methods to retrieve data.

   @page "/custom-form"
   @inject ApplicationDbContext DbContext
   
   @code {
       private List entities;
   
       protected override async Task OnInitializedAsync()
       {
           entities = await DbContext.ExecuteStoredProcedureAsync("yourParameter");
       }
   }
   

4. Bind Data to Forms: Use the retrieved data to populate your custom forms in the Blazor component.

5. This approach allows you to effectively leverage stored procedures and views within your Blazor application, enhancing data retrieval and manipulation capabilities.