Add nested properties to the existing class at runtime and export it to json as per below format-CodePudding

I need to fetch all the table names and their column names from database using an sql query in c# console application and export it to json. The problem is that i don't know what the table names and column names at compile time and i need to add them to the class as property on runtime. The json format should be below:- For example: Database name is mydatabase Tables names are tbl1,tbl2,tbl3 Column names are tbl1(tbl1Col1, tbl1col2), tbl2(tbl2Col1, tbl2col2),tbl3(tbl3Col1, tbl3col2)

Json format should be:

{
  "tables":{
      "tbl1":{
            "columns": {
                  "tbl1Col1":{},
                  "tbl1Col2":{},
            }    
  },
      "tbl2":{
              "columns": {
                  "tbl2Col1":{},
                  "tbl2Col2":{},
            }
  },
      "tbl3":{
             "columns": {
                  "tbl3Col1":{},
                  "tbl3Col2":{},
            }
  }
  }
}

CodePudding user response：

I do have a solution, I was just too tired (caffeine depraved) to notice it, just use a Dictionary, so

class Root // Whatever your class is called
{
    [JsonPropertyName("tables")]
    public Dictionary<string, Table> Tables { get; set; } = new();
}

class Table
{
    [JsonPropertyName("columns")]
    public Dictionary<string, Column> Columns { get; set; } = new();
}

class Column { }

You can then just JsonSerializer,Serialize(root) and it works and produces JSON in the correct structure you want. I created a small demo here to showcase it (don't be alarmed, you can construct your dictionaries however you want, I just used a lot of syntactic sugar)

CodePudding user response：

I think you can work with nested ExpandoObjects.

    [TestMethod]
    public void TestMethod1()
    {
        dynamic rootTables = new ExpandoObject();
        dynamic tables = new ExpandoObject();
        dynamic tbl1Col1 = new ExpandoObject();
        dynamic columns = new ExpandoObject();
        dynamic column = new ExpandoObject();


        AddProperty(column, "tbl1Col1", tbl1Col1);
        AddProperty(columns, "columns", column);
        AddProperty(tables, "tbl1",  columns);
        AddProperty(rootTables, "tables", tables);

        string json = JsonConvert.SerializeObject(rootTables);

        Assert.AreEqual("{\"tables\":{\"tbl1\":{\"columns\":{\"tbl1Col1\":{}}}}}", json);
    }


    public static void AddProperty(ExpandoObject expando, string propertyName, object propertyValue)
    {
        var expandoDict = expando as IDictionary<String, object>;
        if (expandoDict.ContainsKey(propertyName))
            expandoDict[propertyName] = propertyValue;
        else
            expandoDict.Add(propertyName, propertyValue);
    }