how to validate dict in c#

Question

My code as follows

int columnindex = 43;
List<string> lst = new List<string>();

foreach (DataRow row in dtFarmerFarmReports.Rows)
{
var dict = JsonConvert.DeserializeObject<Dictionary<string, string>>(row["farm_detailsdata"].ToString());
if (dict!=null && dict!= string.Empty)
{
string str = string.Empty;
lst.AddRange(dict.Keys);
}

}

when i run shows error as follows
Operator '!=' cannot be applied to operands of type 'Dictionary<string, string>' and 'string'

how to fix this error.

Nitin Sontakke · Answer

Just try removing the problematic piece of code. foreach (DataRow row in dtFarmerFarmReports.Rows) { var dict = JsonConvert.DeserializeObject string , string >>(row[ "farm_detailsdata" ].ToString()); if (dict != null ) { lst.AddRange(dict.Keys); } }

Nitin Sontakke · Answer

It is very simple logic. I am so sorry if you don't understand it. You will need to check if dict is null or not EVERY TIME you access it. You only have put it once where I mentioned, because that is the only portion of the code you showed in the original question. I obviously don't know what is after that. It is your responsibility to put that dict != null check wherever required in the code.

Narasiman nar · Answer

i tried your below code Id Name farmdetailsdata 1 Test1 {"Product1":"A","Product2":"B"} 2 Test2 3 Test3 {"Product1":"C","Product2":"D"} foreach (DataRow row in dtFarmerFarmReports.Rows) { var dict = JsonConvert.DeserializeObject string , string >>(row[ "farm_detailsdata" ].ToString()); if (dict != null ) { lst.AddRange(dict.Keys); } } var distinctList = lst.Distinct().ToList(); List excelheaderlist = new List (); foreach (var data in distinctList) { columnindex++; worksheet.Cells[2, columnindex].Value = data; ExcelHeader excelHeader = new ExcelHeader { colIndex = columnindex, colName = data }; excelheaderlist.Add(excelHeader); } foreach (var dicdata in dict) { int colval = excelheaderlist.Where(x => x.colName == dicdata.Key).Select(y => y.colIndex).FirstOrDefault(); if (colval > 0) { worksheet.Cells[(j1), colval].Value = dicdata.Value; } } from the above validating empty value using dict. when i run the above i get error as follows object reference not set to an instance of object. This error shows in below line as follows foreach (var dicdata in dict). how to fix this error. from my above code what changes i have to make. Becuase in the table for the second farmerid for the column farmdetailsdata value is empty