datacoloumn in asp.net

datacoloumn in asp.net - c#

I first want to add a database column in DataColumn..and then i have to add datacoloumn in datatable.. please guide me;
SqlDataAdapter d2 = new SqlDataAdapter("select MARK_PARTA from exam_cyctstmarkdet",con);
DataColumn c = new DataColumn();
c.ColumnName = "parta";
c.DataType = System.Type.GetType("System.Int32");

Is the bit you're missing
DataTable DT = new DataTable;
d2.Fill(DT);
DT.Columns.Add(c);
???

If you wish to create a DataTable, and add your own columns to it, you can try
DataTable dt = new DataTable("MyTable");
DataColumn col = dt.Columns.Add("parta", typeof(int));
You only have to keep a reference to the column if you plan to use it somewhere, else you can try
DataTable dt = new DataTable("MyTable");
dt.Columns.Add("parta", typeof(int));

I would suggest that you use the SqlDataAdapter to populate a DataSet, which will contain a DataTable. I assume you want to add the new column to this DataTable.
Here's how to do that:
SqlDataAdapter d2 = new SqlDataAdapter("select MARK_PARTA from exam_cyctstmarkdet",con);
DataSet dst = new DataSet();
d2.Fill(dst); // now you have a populated DataSet containing a DataTable
DataTable dt = dst.Tables[0]; // I created this variable for clarity; you don't really need it
DataColumn c = new DataColumn();
c.ColumnName = "parta";
c.DataType = System.Type.GetType("System.Int32");
dt.Add(c);
After you add the Column to the DataTable, the Column will be empty.
You can populate it in code.

Related

How do I add a ListBox item to a DataGridView column header [duplicate]

How do create a DataTable in C#?
I did like this:
DataTable dt = new DataTable();
dt.clear();
dt.Columns.Add("Name");
dt.Columns.Add("Marks");
How do I see the structure of DataTable?
Now I want to add ravi for Name and 500 for Marks. How can I do this?

Here's the code:
DataTable dt = new DataTable();
dt.Clear();
dt.Columns.Add("Name");
dt.Columns.Add("Marks");
DataRow _ravi = dt.NewRow();
_ravi["Name"] = "ravi";
_ravi["Marks"] = "500";
dt.Rows.Add(_ravi);
To see the structure, or rather I'd rephrase it as schema, you can export it to an XML file by doing the following.
To export only the schema/structure, do:
dt.WriteXMLSchema("dtSchemaOrStructure.xml");
Additionally, you can also export your data:
dt.WriteXML("dtDataxml");

You can also pass in an object array as well, like so:
DataTable dt = new DataTable();
dt.Clear();
dt.Columns.Add("Name");
dt.Columns.Add("Marks");
object[] o = { "Ravi", 500 };
dt.Rows.Add(o);
Or even:
dt.Rows.Add(new object[] { "Ravi", 500 });

Create DataTable:
DataTable MyTable = new DataTable(); // 1
DataTable MyTableByName = new DataTable("MyTableName"); // 2
Add column to table:
MyTable.Columns.Add("Id", typeof(int));
MyTable.Columns.Add("Name", typeof(string));
Add row to DataTable method 1:
DataRow row = MyTable.NewRow();
row["Id"] = 1;
row["Name"] = "John";
MyTable.Rows.Add(row);
Add row to DataTable method 2:
MyTable.Rows.Add(2, "Ivan");
Add row to DataTable method 3 (Add row from another table by same structure):
MyTable.ImportRow(MyTableByName.Rows[0]);
Add row to DataTable method 4 (Add row from another table):
MyTable.Rows.Add(MyTable2.Rows[0]["Id"], MyTable2.Rows[0]["Name"]);
Add row to DataTable method 5 (Insert row at an index):
MyTable.Rows.InsertAt(row, 8);

// Create a DataTable and add two Columns to it
DataTable dt=new DataTable();
dt.Columns.Add("Name",typeof(string));
dt.Columns.Add("Age",typeof(int));
// Create a DataRow, add Name and Age data, and add to the DataTable
DataRow dr=dt.NewRow();
dr["Name"]="Mohammad"; // or dr[0]="Mohammad";
dr["Age"]=24; // or dr[1]=24;
dt.Rows.Add(dr);
// Create another DataRow, add Name and Age data, and add to the DataTable
dr=dt.NewRow();
dr["Name"]="Shahnawaz"; // or dr[0]="Shahnawaz";
dr["Age"]=24; // or dr[1]=24;
dt.Rows.Add(dr);
// DataBind to your UI control, if necessary (a GridView, in this example)
GridView1.DataSource=dt;
GridView1.DataBind();

To add a row:
DataRow row = dt.NewRow();
row["Name"] = "Ravi";
row["Marks"] = 500;
dt.Rows.Add(row);
To see the structure:
Table.Columns

You can add Row in a single line
DataTable table = new DataTable();
table.Columns.Add("Dosage", typeof(int));
table.Columns.Add("Drug", typeof(string));
table.Columns.Add("Patient", typeof(string));
table.Columns.Add("Date", typeof(DateTime));
// Here we add five DataRows.
table.Rows.Add(25, "Indocin", "David", DateTime.Now);
table.Rows.Add(50, "Enebrel", "Sam", DateTime.Now);
table.Rows.Add(10, "Hydralazine", "Christoff", DateTime.Now);
table.Rows.Add(21, "Combivent", "Janet", DateTime.Now);
table.Rows.Add(100, "Dilantin", "Melanie", DateTime.Now);

You can write one liner using DataRow.Add(params object[] values) instead of four lines.
dt.Rows.Add("Ravi", "500");
As you create new DataTable object, there seems no need to Clear DataTable in very next statement. You can also use DataTable.Columns.AddRange to add columns with on statement. Complete code would be.
DataTable dt = new DataTable();
dt.Columns.AddRange(new DataColumn[] { new DataColumn("Name"), new DataColumn("Marks") });
dt.Rows.Add("Ravi", "500");

The easiest way is to create a DtaTable as of now
DataTable table = new DataTable
{
Columns = {
"Name", // typeof(string) is implied
{"Marks", typeof(int)}
},
TableName = "MarksTable" //optional
};
table.Rows.Add("ravi", 500);

DataTable dt=new DataTable();
Datacolumn Name = new DataColumn("Name");
Name.DataType= typeoff(string);
Name.AllowDBNull=false; //set as null or not the default is true i.e null
Name.MaxLength=20; //sets the length the default is -1 which is max(no limit)
dt.Columns.Add(Name);
Datacolumn Age = new DataColumn("Age", typeoff(int));`
dt.Columns.Add(Age);
DataRow dr=dt.NewRow();
dr["Name"]="Mohammad Adem"; // or dr[0]="Mohammad Adem";
dr["Age"]=33; // or dr[1]=33;
dt.add.rows(dr);
dr=dt.NewRow();
dr["Name"]="Zahara"; // or dr[0]="Zahara";
dr["Age"]=22; // or dr[1]=22;
dt.rows.add(dr);
Gv.DataSource=dt;
Gv.DataBind();

DataTable dt=new DataTable();
DataColumn Name = new DataColumn("Name",typeof(string));
dt.Columns.Add(Name);
DataColumn Age = new DataColumn("Age", typeof(int));`
dt.Columns.Add(Age);
DataRow dr=dt.NewRow();
dr["Name"]="Kavitha Reddy";
dr["Age"]=24;
dt.add.Rows(dr);
dr=dt.NewRow();
dr["Name"]="Kiran Reddy";
dr["Age"]=23;
dt.Rows.add(dr);
Gv.DataSource=dt;
Gv.DataBind();

You have to add datarows to your datatable for this.
// Creates a new DataRow with the same schema as the table.
DataRow dr = dt.NewRow();
// Fill the values
dr["Name"] = "Name";
dr["Marks"] = "Marks";
// Add the row to the rows collection
dt.Rows.Add ( dr );

In addition to the other answers.
If you control the structure of the DataTable there is a shortcut for adding rows:
// Assume you have a data table defined as in your example named dt
dt.Rows.Add("Name", "Marks");
The DataRowCollection.Add() method has an overload that takes a param array of objects. This method lets you pass as many values as needed, but they must be in the same order as the columns are defined in the table.
So while this is a convenient way to add row data, it can be risky to use. If the table structure changes your code will fail.

Question 1: How do create a DataTable in C#?
Answer 1:
DataTable dt = new DataTable(); // DataTable created
// Add columns in your DataTable
dt.Columns.Add("Name");
dt.Columns.Add("Marks");
Note: There is no need to Clear() the DataTable after creating it.
Question 2: How to add row(s)?
Answer 2: Add one row:
dt.Rows.Add("Ravi","500");
Add multiple rows: use ForEach loop
DataTable dt2 = (DataTable)Session["CartData"]; // This DataTable contains multiple records
foreach (DataRow dr in dt2.Rows)
{
dt.Rows.Add(dr["Name"], dr["Marks"]);
}

Create datatabe with 2 columns: Name & Marks
IList columns = new List() {"Name", "Marks"};
Datatabel dt = new Datatable();
foreach (string column in columns)
dtSalesOrder.Columns.Add(column, typeof(string));
Add data to datatable
dt.Rows.Add("Ravi","500");

setOrdinal not working properly when table is bind to datasource

When I try to add new column and use SetOrdinal(2)
The newly added column was positioned in the last column
conn = new MySqlConnection(connectString);
conn.Open();
fireAdapter = new MySqlDataAdapter(query, conn);
fireBuilder = new MySqlCommandBuilder(fireAdapter);
fireDataTable = new DataTable();
fireAdapter.Fill(fireDataTable);
fireSource = new BindingSource();
fireSource.DataSource = fireDataTable;
grid.DataSource = fireSource;
conn.Close();
DataColumn newcol = new DataColumn("Blah", typeof(string));
fireDataTable.Columns.Add(newcol);
newcol.SetOrdinal(2);

I'm pretty sure that your code does what you expect, it changes the position of the new column in the DataTable. But it is still shown as last column in the grid. So why you don't initialize the BindingSource after you have fully initialized the DataTable?
DataColumn newcol = new DataColumn("Blah", typeof(string));
fireDataTable.Columns.Add(newcol);
newcol.SetOrdinal(2);
// and now start assign it to the BindingSource

c# wpf new data overwrite previous data [duplicate]

This question already exists:
c# datagrid sql population
Closed 5 years ago.
I am working with a small application where the user can retrieve specific data from SQL populate the datagrid with the data. The user can retrieve data from SQL Database where he write a barcode in textbox then the data he searched for will appear.
Until now i used this code
if (e.Key == Key.Enter)
{
SqlConnection con = new SqlConnection("Server = localhost;Database = Bilanc; Integrated Security = true");
SqlCommand cmd = new SqlCommand("product", con); // Using a Store Procedure.
cmd.CommandType = CommandType.StoredProcedure;
DataTable dt = new DataTable("dtList");
cmd.Parameters.AddWithValue("#Barcod", txtcode.Text);
DataTable dataTable = new DataTable();//Created a new DataTable
DataColumn dc = new DataColumn();//Made a new DataColumn to populate above DataTable
dc.DataType = System.Type.GetType("System.String");//Defined the DataType inside, this can be [[int]] if you want.
dc.ColumnName = "#Barcod";//Gave it a name (important for the custom expression - can only be one word so use underscores if you need multiple words)
DataColumn dc2 = new DataColumn();
dc2.DataType = System.Type.GetType("System.String");
dc2.ColumnName = "#Product";
DataColumn dc3 = new DataColumn();
dc3.DataType = System.Type.GetType("System.Decimal");
dc3.ColumnName = "#QTY";
DataColumn dc4 = new DataColumn();
dc4.DataType = System.Type.GetType("System.Decimal");
dc4.ColumnName = "#Price";
DataColumn dc5 = new DataColumn();
dc5.DataType = System.Type.GetType("System.String");
dc5.ColumnName = "#Tax";
DataColumn dc6 = new DataColumn();
dc6.DataType = System.Type.GetType("System.String");
dc6.ColumnName = "Total";
dc6.Expression = "#Price * #QTY";//Multiplying the Price and Quantity DataColumns
dataTable.Columns.Add(dc);//Add them to the DataTable
dataTable.Columns.Add(dc2);
dataTable.Columns.Add(dc3);
dataTable.Columns.Add(dc4);
dataTable.Columns.Add(dc5);
dataTable.Columns.Add(dc6);
dtg.ItemsSource = dataTable.DefaultView;//Set the DataGrid ItemSource to this new generated DataTable
con.Open();//Open the SQL connection
SqlDataReader reader = cmd.ExecuteReader();//Create a SqlDataReader
while (reader.Read())//For each row that the SQL query returns do
{
DataRow dr = dataTable.NewRow();//Create new DataRow to populate the DataTable (which is currently binded to the DataGrid)
dr[0] = reader[0];//Fill DataTable column 0 current row (Product) with reader[0] (Product from sql)
dr[1] = reader[1];
dr[2] = reader[2];
dr[3] = reader[3];
dr[4] = reader[4];
dataTable.Rows.Add(dr);//Add the new created DataRow to the DataTable
}
}
}
The code works fine, but when i got stuck is when i retrieve data from SQL the new data overwrite the previous data.
My question how i can keep the previous data
Thanks to everyone

Try the InsertAt() method instead of Add() of datatable with the appropriate position parameter.

How can I convert a datatable to a related dataset

I have denormalized data in a DataTable.
The data contains employee names, and the pay they got over a series of pay cycles. i.e.:
My DataTable contains:
Employee 1 Jan-1-2012 $100
Employee 2 Jan-1-2012 $300
Employee 1 Feb-1-2012 $400
Employee 2 Feb-1-2012 $200
Employee 1 Mar-1-2012 $150
Employee 2 Mar-1-2012 $325
How can load this data into a DataSet where the parent DataTable contains the employees name, and the child DataTable contains details of the paycheck?

DataSet is nothing but a collection of DataTables. So to "load" the dataTable into dataSet simple Add it:
DataTable employees = new DataTable();
DataTable payCheckes = new DataTable();
DataSet ds = new DataSet();
ds.Tables.Add(employees);
ds.Tables.Add(payCheckes);
Do you want to "combine" datatables somehow?
Get paycheckes of each employee?

the code without manual insert:
DataSet ds = new DataSet();
DataTable dtemploye = new DataTable();
DataTable dtpayment = new DataTable();
ds.Tables.AddRange(new DataTable[] { dtemploye, dtpayment });
DataColumn dcIdemploye = dtemploye.Columns["ID_EMPLOYEE"];
DataColumn dcIdemployeprice = dtpayment.Columns["ID_EMPLOYEE"];
DataRelation drrelation = new DataRelation("relemploy_payment", dcIdemploye, dcIdemployeprice);
ds.Relations.Add(drrelation);

DataSet ds = new DataSet();
DataTable dtemploye = new DataTable();
DataColumn dcnameemploye = new DataColumn();
DataColumn dcIdemploye = new DataColumn();
dtemploye.Columns.AddRange(new DataColumn[]{dcnameemploye,dcIdemploye});
DataTable dtpayment = new DataTable();
DataColumn dtprice = new DataColumn();
DataColumn dtDate = new DataColumn();
DataColumn dcIdemployeprice = new DataColumn();
dtpayment.Columns.AddRange(new DataColumn[]{dcIdemployeprice,dtprice,dtDate});
DataRow drrowemploy = dtemploye.NewRow();
drrowemploy[0] = "1";
drrowemploy[1] = "Employee 1";
dtemploye.Rows.Add(drrowemploy);
DataRow drrowpayment = dtpayment.NewRow();
drrowpayment[0] = "1";
drrowpayment[0] = "01/01/2012";
drrowpayment[1] = " 300";
ds.Tables.AddRange(new DataTable[]{dtemploye, dtpayment});
DataRelation drrelation = new DataRelation("relemploy_payment", dcIdemploye, dcIdemployeprice);
ds.Relations.Add(drrelation);

how to insert data to dataset

i have this making table:
DataTable WorkTbl()
{
DataTable Work= new DataTable("Work"); //Table Name
DataColumn MAC = new DataColumn("MAC", typeof(string));
DataColumn ID_OLD = new DataColumn("ID_OLD", typeof(string));
Work.Columns.Add(MAC);
Work.Columns.Add(ID_OLD);
return Work;
}
how to insert data to this table and how to convert this table to Dataset ?
thanks in advance

From MSDN:
DataRow workRow = workTable.NewRow();
You then can manipulate the newly added row using an index or the column name, as shown in the following example.
workRow["CustLName"] = "Smith";
workRow[1] = "Smith";
DataSet customerOrders = new DataSet("CustomerOrders");
DataTable ordersTable = customerOrders.Tables.Add("Orders");
DataColumn pkOrderID =
ordersTable.Columns.Add("OrderID", typeof(Int32));
ordersTable.Columns.Add("OrderQuantity", typeof(Int32));
ordersTable.Columns.Add("CompanyName", typeof(string));
ordersTable.PrimaryKey = new DataColumn[] { pkOrderID };

Develop Reference

C# (C-Sharp) is a programming language developed by Microsoft that runs on the .NET Framework.

datacoloumn in asp.net - c#

Is the bit you're missing DataTable DT = new DataTable; d2.Fill(DT); DT.Columns.Add(c); ???

Related

How do I add a ListBox item to a DataGridView column header [duplicate]

setOrdinal not working properly when table is bind to datasource

c# wpf new data overwrite previous data [duplicate]

How can I convert a datatable to a related dataset

how to insert data to dataset

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