Develop Reference

Trying to get second row from DataTable

I'm trying to retrieve the second row from a DataTable but this is not returning a value. What could be the problem as the DropDown populates just fine.
using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
{
DataTable dt = new DataTable();
sda.Fill(dt);
DropDown.DataSource = dt;
DropDown.DataTextField = "FirstName";
DropDown.DataValueField = "FirstName";
DropDown.DataBind();
con.Close();
var secondRow = dt.Rows[2].ToString(); // This should return the second row in my datatable.
}

DataTable.Rows[int] will give you the DataRow object. If you do dt.Rows[2].ToString(), you are going to get the string representation of the object type.
The index starts at 0. Hence for 2nd row, you will query dt.Rows[1]. Further, You can extract the value of a column in the row and for that, you have to mention the column index or name like - dt.Rows[1][0] or dt.Rows[1]["col1"]
You can also loop through all the columns in the row like below:
foreach (DataColumn col in dt.Columns)
{
var columnValue = dt.Rows[1][col];
}

How do I search data in from datatable based on user input

I have created one datatable:
DataTable dt=new DataTable();
dt.Columns.Add("Country", typeof(string))
dt.Columns.Add("place", typeof(string))
dt.Columns.Add("Price", typeof(string))
dt.Columns.Add("Desc", typeof(string))
and I have inserted some data in this datatable:
DataRow dtrow = dt.NewRow(); // Create New Row
dtrow["Country"] = "India"; //Bind Data to Columns
dtrow["place"] = "wizag";
dtrow["Price"] = "7520";
dtrow["Desc"] = "Anywhere";
dt.Rows.Add(dtrow);
dtrow = dt.NewRow(); // Create New Row
dtrow["Country"] = "India"; //Bind Data to Columns
dtrow["place"] = "Goa";
dtrow["price"] = "4500";
dtrow["Desc"] = "Anything";
dt.Rows.Add(dtrow);
I have bind this datatable with my grid view. I have also added one textbox and one search button in mmy aspx page. My requirement is that I want to search data based on user input e.g like 4500 or wizag, and if country name is the same I want to show it in one row
How can I do this?

I would use a DataView in this case
DataView dv = new DataView(dt);
dv.RowFilter = "price = 4500 AND Country = 'India'";
GridView.DataSource = dv.ToTable();
GridView.DataBind();

Checking value in column foreach row

The DataTable (dt) stores the retrieved values of carID's and makes so it stores like 3 rows within the DataTable, I also have another DataTable called dt2 which also stores carID's and makes, I am trying to loop through each row in the dt to see if any carID stored in the dt exists in any of the rows in dt2, here is what I have so far:
DataTable dt = w.getUserCars(userID);
foreach (DataRow dr in dt.Rows)
{
string carID = dr["carID"].ToString();
}
How do I do this?

You should be able to achieve this using DataTable.Select() method. You are on the right track. You just need to add the method to find the Row(s) in dt2.
DataTable dt = w.getUserCars(userID);
DataRow[] foundRows;
foreach (DataRow dr in dt.Rows)
{
string carID = dr["carID"].ToString();
foundRows = dt2.Select("carID = " + carID);
// do stuff here with foundRows
foreach (DataRow r in foundRows)
{
r.Delete();
}
}

How to bind DataRow to the GridView?

I have one datatable which has four or five columns. I dont know exactly the columns name and its count. But I want to bind the first row of the datatable into the GridView. How to do this? I need all your suggestions please.

Linq should be helpful here to get first item.
var Temp = dt.AsEnumerable().Take(1).CopyToDataTable();

use the filter in the datatable :
dt.Select("ID = 1");

you can try like this..
dt = new DataTable();
dt_Property.Columns.Add("Field1");
int i = 0;
DataRow row = null;
foreach (DataRow r in ds.Tables[0].Rows)
{
row = dt.NewRow();
row["Field1"] = ds.Tables[0].Rows[i][1];
dt_Property.Rows.Add(row);
i = i + 1;
}
dataGridView1.DataSource = dt;

C# Adding a Datatable to a Datatable

I know that sounds really weird, but I am fairly new to C# and I am hoping you guys can help me out.
I am looping thru a DataTable, then excute a qry and get the the result into a DataTable.
Works OK for one record, but as soon as there are more records, only the last record is in the DT, which makes sense, I just do not know how to fix it. I need to have all the records in the DT.
Here is my code, any suggestions are welcome....
DataTable dt = ml.getRegistration();
DataTable dt2 = new DataTable();
foreach (DataRow row in dt.Rows)
{
dt2 = ml.getRegistrationExport(row["ID"]);
}
GridView1.DataSource = dt2;
GridView1.DataBind();

If ml.getRegistrationExport is returning a datatable, then it overwrites the data as you loop through the first datatable.. You need to use dt2.merge to add all the data to the datatable. HTH.
DataTable dt = ml.getRegistration();
DataTable dt2 = new DataTable();
foreach (DataRow row in dt.Rows)
{
dt2.merge(ml.getRegistrationExport(row["ID"]));
}
GridView1.DataSource = dt2;
GridView1.DataBind();

One of the problems I see is each row you are looping through you are replace dt2. So if you have 5 rows, you will replace dt2 5 times and which ever row happen to be last would rule dt2.
I would re think this.
Are what you are trying to do is add a row to dt2 for each row in the original dt?
DataTable dt = ml.getRegistration();
DataTable dt2 = new DataTable();
foreach (DataRow row in dt.Rows)
{
DataRow newRow = dt2.NewRow();
// What Does getRegistrationExport return?
// A row or series of rows or a new DT?
// Each would change solution
newRow["SomeColumn"] = ml.getRegistrationExport(row["ID"]);
dt2.Rows.Add(newRow);
}
GridView1.DataSource = dt2;
GridView1.DataBind();