Returning object as JSON data using Web API C#

Question

I want to generate JSON data from a database table using Web API C#.The following is the table structure

CREATE TABLE [dbo].[Fields](
    [fieldID] [varchar](250) NOT NULL,
    [displayName] [varchar](500) NOT NULL,
    [id] [bigint] NOT NULL,
    [tenant] [bigint] NOT NULL,
    [Name] [varchar](500) NOT NULL,
    [description] [varchar](500) NULL,
    [type] [varchar](250) NULL
) ON [PRIMARY]
GO

And having following data

INSERT [dbo].[Fields] ([fieldID], [displayName], [id], [tenant], [Name], [description], [type]) VALUES (N'100', N'Loan#', 18, 3, N'Loan#', N'Loan#', N'string')
GO
INSERT [dbo].[Fields] ([fieldID], [displayName], [id], [tenant], [Name], [description], [type]) VALUES (N'101', N'LoanProgram', 19, 3, N'LoanProgram', N'LoanProgram', N'string')
GO

From this table and I want to generate a JSON in the following format using the Web API

{
  "100": {
        "fieldID": "100",
        "displayName": "Loan#",
        "id": 18,
        "tenant": 3,
        "name": "Loan#",
        "description": "Loan#",
        "type": "string"        
    },
    "101": {
        "fieldID": "101",
        "displayName": "LoanProgram",
        "id": 19,
        "tenant": 3,
        "name": "LoanProgram",
        "description": "LoanProgram",
        "type": "string"        
    }
}

Following is my API controller

[HttpGet("Fields/{id}/fields/")]
public Object GetFields(int id)
{
   return _fieldService.GetFields(id).Result;
}

I have created a class as follows

public class ConfiguredFields
{
    public int fieldID { get; set; }
    public string displayName { get; set; }
    public int id { get; set; }
    public string tenant { get; set; }
    public string name { get; set; }
    public string description { get; set; }
    public string type { get; set; }        
}

And using Dapper I have called the SP and tried to the value

public async Task<Object> GetWorkflowFields(int WID)
{
    using (var db = new SqlConnection(_connectionString.Value))
    {
        var parameters = new DynamicParameters();
        parameters.Add("@pm_ID", WID);
        var result = await db.QueryAsync<ConfiguredFields>("SP_GetLoanFields", parameters, commandType: CommandType.StoredProcedure);

        
        return result.ToList();

    }
}

But I am getting the JSON in the following format (with array lap and not in the desired format where fieldID wise wrapping is not there.)

[
    {
        "fieldID": 100,
        "displayName": "Loan#",
        "id": 18,
        "tenant": "3",
        "name": "Loan#",
        "description": "Loan#",
        "type": "string"        
    },
    {
        "fieldID": 101,
        "displayName": "LoanProgram",
        "id": 19,
        "tenant": "3",
        "name": "LoanProgram",
        "description": "LoanProgram",
        "type": "string"   
    }
    
]

Please suggest what all changes required here to get the JSON in desired format? Please help me to solve this?

Answer 1

1. Change the return type of your GetWorkflowFields method from Task<Object> to Task<List<ConfiguredFields>> :

    public async Task<List<ConfiguredFields>> GetWorkflowFields(int WID) {... }

2. Change your model properties to have types that match the data in your database (based on the table definition you gave in your question).

   Change fieldID from int to string .
   Change id from int to long .
   Change tenant from string to long .

    public class ConfiguredFields { public string fieldID { get; set; } public string displayName { get; set; } public long id { get; set; } public long tenant { get; set; } public string name { get; set; } public string description { get; set; } public string type { get; set; } }

3. Change your GetFields controller method to convert the result from GetWorkflowFields to a dictionary:

    return _fieldService.GetWorkflowFields(id).Result.ToDictionary(f => f.fieldID);

4. (Optional, but recommended) Change the return type of the GetFields controller method to Dictionary<string, ConfiguredFields> . Better yet, make the method async :

    [HttpGet("Fields/{id}/fields/")] public async Task<Dictionary<string, ConfiguredFields>> GetFields(int id) { var fields = await _fieldService.GetWorkflowFields(id); return fields.ToDictionary(f => f.fieldID); }