asked on

How can i convert the contents of a list into a dataset and make it available anywhere in my application

In my c# application I need to read a set of data from a table "stateorigin"
and get it ready as a dataset for preparing a crystal report

I have 2 scripts

My first script defines the fields in the dataset ( see script below)

//Creates a new dataset, 2 datatables and adds data to them
_dsData = new DataSet("TestDataSet");

  private void CreateDataSet2()
        {
            //Creates a new dataset, 2 datatables and adds data to them
            _dsData = new DataSet("TestDataSet");

            //byte[] arrBytes;
            //System.IO.MemoryStream ms;

            using (DataTable dt = new DataTable("stateorigin"))
            {
                dt.Columns.Add("stateid", typeof(int));
                dt.Columns.Add("statedescription", typeof(string));
              
                GlobalConfig.Connection.GetStateCode_All();

                _dsData.Tables.Add(dt);
            }
         
        }

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So basically I want to read 2 fields stateid and statedescription from stateorigin table

Already during the creation of my application i have a script that get a list of these same fields BUT

into a list. ( See script below )

[public List<StateOriginModel> GetStateCode_All()
{
List<StateOriginModel> results = new List<StateOriginModel>();

using (var conn = new NpgsqlConnection(pgrstring))
{
using (NpgsqlCommand command = new NpgsqlCommand("public.spstateorigincode_getall", conn))
{
conn.Open();
command.CommandType = CommandType.StoredProcedure;
command.Parameters.Add(new NpgsqlParameter("countrycodex", NpgsqlTypes.NpgsqlDbType.Varchar) { Direction = ParameterDirection.Input, Value = LoginDetails.staticcountry.ToUpper() });

var reader = command.ExecuteReader();

if (reader.HasRows)
{
while (reader.Read())
{
StateOriginModel model = new StateOriginModel();

if ((string)reader["StateID"] != null)
{
model.Id = (int)reader["id"];
model.StateID = (string)reader["StateID"];
model.StateDescription = (string)reader["StateDescription"];
results.Add(model);
}
}
}
}
}
return results;
}[/code]

Using the debugger i know that the List is populated into a list called results

My questions are

1. Is there a way for me to assign the contents of the list results to the dataset _dsData

2. I need to make the contents of _dsData available to the calling script 1
How do i define _dsData as a static class so that i can get its data anywhere in my application

Thanks

Olukay

Éric Moreau

Have a look at this code snippet: https://www.dotnetperls.com/convert-list-datatable

Eduard Ghergu

Hi,

If you don't have any other reason for having the results list, you can use a SqlDataAdapter for reading the data and fill the DataSet. You have a sample here:
https://www.webtrainingroom.com/adonet/dataset

Olukayode Oluwole

ASKER

Hello Mike
The topic is related to Crystal Reports ( Please ask Eric who will confirm
that this is a first step in creating a .NET report in Crystal Reports)

I am trying to create a dataset that will be an input
into my CrystalReportViewer

I was trying to narrow the issue to where i currently have an error so that
the expert helping will focus on where i have a problem

I need to get back to Eric on my efforts and how far i have gone with his suggestion

How do I progress

Thanks

Olukay

Éric Moreau

I have already provided a link to transform a list into a datatable (and that datatable can be added to a dataset). Also the idea of Eduard to fill the dataset right from the database can also be used.

Olukayode Oluwole

ASKER

Thanks Eric for opening this thread again.

I need both the list and the DataTable so will be going with the snippet you sent

I have tried to get the data table working with the 2 scripts below.

The first is my old list and it then call the new script that should prepare the DataTable (see below)

[] public List<StateOriginModel> GetStateCode_All()
{
List<StateOriginModel> results = new List<StateOriginModel>();

using (var conn = new NpgsqlConnection(pgrstring))
{
using (NpgsqlCommand command = new NpgsqlCommand("public.spstateorigincode_getall", conn))
{
conn.Open();
command.CommandType = CommandType.StoredProcedure;
command.Parameters.Add(new NpgsqlParameter("countrycodex", NpgsqlTypes.NpgsqlDbType.Varchar) { Direction = ParameterDirection.Input, Value = LoginDetails.staticcountry.ToUpper() });

var reader = command.ExecuteReader();
// Bring in Parameters to limit selection to Login.Staticcompany
if (reader.HasRows)
{
while (reader.Read())
{
StateOriginModel model = new StateOriginModel();

if ((string)reader["StateID"] != null)
{
model.Id = (int)reader["id"];
model.StateID = (string)reader["StateID"];
model.StateDescription = (string)reader["StateDescription"];
results.Add(model);

}
}
}
}
}

DataTable table = ConvertListToDataTable(results);
return results;
}

private DataTable ConvertListToDataTable(List<StateOriginModel> results)
{
DataTable table = new DataTable();

// Get max columns.
int columns = 0;
foreach (var array in results)
{
if (array.Length > columns)
{
columns = array.Length;
}
}

// Add columns.
for (int i = 0; i < columns; i++)
{
table.Columns.Add();
}

// Add rows.
foreach (var array in results)
{
table.Rows.Add(array);
}

return table;
}[/code]

Where I have an issue is that my list is not being seen as an array

So array length is zero even though it should not be (see the 2 screens below)

And then because array length is zero i have another error down the line (see below)

I have tried to see how to specify that the list should be prepared as an array but i keep

having error.

Please assist to check what i might be doing wrong

Olukay

Éric Moreau

stupid question but I will ask anyway: do you have data in your list?

Eduard Ghergu

Hi,

foreach (var array in results)
{
table.Rows.Add(array);
}

array is an instance of StateOriginModel class, is not an array. You can implement a method to convert a such object to an array, if you want.

Olukayode Oluwole

ASKER

Answer to the first question is YES . The List contains data
The list has 36 rows and below is a typical row data as shown in the debugger

Typical data in List But Strangely showing Array length as Zero

The new error screen after trying Eduard suggestion is attached below

New Array Error after Trying Eduard Suggestion is shown below

I assumed Eduard wants me to comment out everything and just have what he has
in his suggestion ie

foreach (var array in results) {
table.Rows.Add(array);
}

Thats exactly what I have done

What should i try to resolve this error

Thanks

Olukay

Eduard Ghergu

Hi,
How your method for creating an array from StateOriginModel looks like?

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Éric Moreau

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Olukayode Oluwole

ASKER

Thanks for the suggestions

Will now go ahead to fix the last 2 steps of generating the report.