extract values from DataTable with single row

Question

How to extract the values from data table having single row and assign to asp labels.

private void GetUser(string userId)
{
    dbr.SelectString = "select name, gender,  address, contactno from userInfo where id = = '" + userId + "' --"; // return single row
    DataTable dt = dbr.GetTable();
    //DataRow row = dt.Rows[0];
    // how to retrieve the fields from the data table.
    //lbl_name = name.ToString();
    //lbl_gender = gender.ToString();
    //lbl_contact = contactno.ToString();
}

I thought of using foreach loop but the datatable contains only single row. How can I pass empty string in the case of NULL cells. Also, can I extract the values from datatable via list?

ASh · Accepted Answer · 2019-08-07T14:53:12.573

24

private void GetUser(string userId)
{
    dbr.SelectString = "select name, gender,  address, contactno from userInfo where id = = '" + userId + "' --"; // return single row
    DataTable dt = dbr.GetTable();
    if (dt.Rows.Count > 0) 
    {
        DataRow row = dt.Rows[0];

        lbl_name = row["name"].ToString();
        lbl_gender = row["gender"].ToString();
        lbl_contact = row["contactno"].ToString();
    }
}

edited Aug 07 '19 at 14:53

answered Mar 14 '15 at 07:52

ASh

34,632
9
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thanks for the prompt reply. can I convert this data table to list and retrieve values. Which will be more preferably? Please can you explain. – user4221591 Mar 14 '15 at 08:03
@user4221591, which kind of list? dataTable contains 1 row, create a single object of custom type – ASh Mar 14 '15 at 19:24

score 3 · Answer 2 · answered Dec 04 '19 at 13:54

Simply in one line

dbr.SelectString = "select name, gender,  address, contactno from userInfo where id = = '" + userId + "' --"; 
DataTable DataTable_Values= dbr.GetTable(); 
lbl_name =  DataTable_Values.Rows[0].Field<string>("name");
lbl_gender =  DataTable_Values.Rows[0].Field<int>("gender");
lbl_contact =  DataTable_Values.Rows[0].Field<int>("contact")

score 0 · Answer 3 · answered Mar 14 '15 at 08:50

0

To get an list of all Rows, you need a Class

  class Lbl()
            {
                public string Name {get; set;}
                public string Gender {get; set;}
                public string Contact {get; set;}
            }

Fill the class:

 List<Lbl> list = new List<Lbl>();
            foreach(DataRow row in dt.Rows)
            {
                Lbl lbl = new Lbl();
                lbl.Name = row["name"].ToString();
                lbl.Gender = row["gender"].ToString();
                lbl.Contact = row["contactno"].ToString();

                list.add(lbl);
            }

answered Mar 14 '15 at 08:50

Thomas

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how to handle if the columns return NULL values. Please can you share. – user4221591 Mar 14 '15 at 10:43
object value = row["name"]; if (!value == DBNull.Value) { } else { } – Thomas Mar 14 '15 at 12:08
in MsSQL you can use the IsNull-Method: SELECT ISNULL(name,'') AS name – Thomas Mar 14 '15 at 12:13
1

@user4221591, value of dataRow cell can never be null. NULL from db will be converted into DbNull.Value – ASh Mar 14 '15 at 19:22

score 0 · Answer 4 · answered Feb 10 '20 at 18:38

its quite late but I think what you are looking for is the below code, this Datatable is the result of a query. That DT is then being parsed with all its rows and columns as a string.

DataTable dt = Execute_Query(Connection, query);
            if (dt != null)
            {
                if (dt.Rows.Count > 0)
                {
                    J = dt.Rows.Count;

                    StringBuilder sb = new StringBuilder();

                    for (int i = 0; i < dt.Rows.Count; i++)
                    {
                        for (int j = 0; j < dt.Columns.Count; j++) 
                        {
                            sb.Append(dt.Rows[i][j] + ",");
                        }
                        sb.Append("\n");
                    }

                    Logger.Info(sb.ToString());
                }
            }

extract values from DataTable with single row

4 Answers4