I have a datarow, but how can i convert it to an int ?
I tried this, but it doesn't work.
dsMovie = (DataSet)wsMovie.getKlantId();
tabel = dsMovie.Tables["tbl_klanten"];
eersteRij = tabel.Rows[0];
(Int32.Parse(eersteRij.ToString())
A DataRow is an object; it is not an integer. A DataRow contains one or more columns of data. You can index into the DataRow to access the values of these coulmns.
If table tbl_klanten contains one column, and that column is an integer, you can do the following:
var myInt = (int)eersteRij[0];
if the column is a string containing the value of an integer,
var myInt = int.Parse(eersteRij[0]);
If the column is named klant_id...
var myInt = (int)eersteRij["klant_id"];
if the column is a string containing the value of an integer,
var myInt = int.Parse(eersteRij["klant_id"]);
Simply use the Field method:
int result = row.Field<int>("ColName");
The Field method also supports nullable types:
The Field method provides support for accessing columns as nullable
types. If the underlying value in the DataSet is Value, the returned
nullable type will have a value of null.
And please notice:
The Field method does not perform type conversions. If type conversion is required, you should first obtain the column value by using the Field method. The column value should then be converted to another type.
Because even at that level of hierarchy you still have a DataRow and you can't convert a DataRow to int.. a value could be converted though.
And why are you converting whole DataRow to int.. usually you would like to get a value in a cell at a row so try, Somthing like this:
int value = (int)eersteRij.Items[0];
where 0 can be replaced by the cell position(int) or Column name(string)
You'll need to know which index the object you want is on, and cast that to an int, e.g.:
int value = (int)eersteRij[0];
DataSet dataSet = getDataFromDatabase();
DataRow tableRow = dataSet.Tables[0].Rows[0];
int valueAsInteger = Convert.ToInt32(tableRow["COLUMN_NAME"]);
I tend to use IndexOf() when looping thru the dataTable.
foreach (DataRow row in DataTable.table.Rows)
{
int index = dataTable.Rows.IndexOf(row);
}
Related
Am trying to get a a Zero indexed Value from a column in the TableAdpter but it has refused , how can i retrieve a value in the Column index Zero , below is my code :
LoginTableAdapter l = new LoginTableAdapter();
string res = l.GetData("mueat", "1234").Rows[0].ToString();
And my table which is attached to the TableAdapter is as below , it's one column and i want to get the value t which is in a Zero index in the column access:
If we assume l.GetData("mueat", "1234") returns a DataTable, like so:
DataTable table = l.GetData("mueat", "1234"); // the dataTable
then this:
DataRow row = table.Rows[0]; // first row;
will only give you the first row out of the DataRowCollection's indexer
As we can see on the DataRow type, it has an indexer as well, giving access to the columns in the DataRow instance.
object columnValue = row[0]; // first column
You can now cast the object value to the correct type or call ToString on it to convert it to its string representation.
Putting this all back together in your compact one-liner you will get:
string res = l.GetData("mueat", "1234").Rows[0][0].ToString();
I am having one integer column in a data table and I want to set null value in that column. I have done AllowDBNull true but still it doesn't work if a null value is getting added.
Following are the configuration which I have done for Column
I am getting following exception
Can anyone help mi for this?
You can't assign DBNull to a field in the DataTable. When you allow DBNull in a DataTable, an extra method is generated. In this case: SetParentApplicationRoleIdNull()
for example:
var newRow = DataSet.ChildApplications.NewChildApplicationRow();
newRow.AField = "Some text";
newRow.SetParentApplicationRoleIdNull();
DataSet.ChildApplications.AddChildApplicationRow(newRow);
This is also while checking the value. You can't directly use the 'property' ParentApplicationRoleId, If you want to read it, you'll have the check it first with another generated method: IsParentApplicationRoleIdNull()
for example:
foreach(var row in DataSet.ChildApplications.Rows)
{
if(!row.IsParentApplicationRoleIdNull())
{
Trace.WriteLine($"ParentApplicationRoleId: {row.ParentApplicationRoleId}");
}
else
{
Trace.WriteLine("ParentApplicationRoleId: is DBNull, and can't be shown");
}
}
The "?" behind a datatype makes it nullable.
Example:
int? t = null;
So nzrytmn is right!
You can try setting the NullValue property of the data column to something that is not "(ThrowException)"
Did you try set DataType as Sytem.Int32? May it have to be nullable.
Could you pls check this answer Table is nullable DateTime, but DataSet throws an exception?
Please declare that value as nullable int(int?). then it will accet all null values
Is it possible to have a DataColumn in a DataTable that contains int and long values? It should return an int value if a valid int else it should return a long value.
For some background why I want to achieve this, I have released a product that creates the DataColumn of type int, but it should have been long from the start. Now I don't want to break existing projects that explicitly casts the value to int, but I would like to allow long values in the column.
Is there an event I can subscribe to on the DataTable to convert the value to int?
The following code should execute correctly.
DataTable dataTable = new DataTable();
dataTable.Columns.Add("IntAndLong", typeof(long));
DataRow intRow = dataTable.NewRow();
intRow[0] = 123;
dataTable.Rows.Add(intRow);
DataRow longRow = dataTable.NewRow();
longRow[0] = 3000000000;
dataTable.Rows.Add(longRow);
long longValue = (long)dataTable.Rows[1][0];
int intValue = (int)dataTable.Rows[0][0];
I would suggest collecting the datacolumn value in a long type variable, check its value to be less than int.MaxValue and bigger than int.MinValue and then cast it to an int variable if you need it there.
I have a database command that populates a DataTable I want to get the value of an entry in the Datatable, based on, A: The numeral index of the row, and b, the string name of the column. That's all I want, how is that possible?
yourDatatable.Rows[rowIndex]["columnName"] should work
myTbl.Rows[0]["b"];
A is not a row index.
DataTable dt = GetData();
var result = dt.Rows[RowIndex]["MyColumnName"];
The RowIndex is an indexed property of the datatable which returns a DataRow. "MyColumnName" is an indexed property of the DataRow, returning the value as an object.
I have a dataview defined as:
DataView dvPricing = historicalPricing.GetAuctionData().DefaultView;
This is what I have tried, but it returns the name, not the value in the column:
dvPricing.ToTable().Columns["GrossPerPop"].ToString();
You need to specify the row for which you want to get the value. I would probably be more along the lines of table.Rows[index]["GrossPerPop"].ToString()
You need to use a DataRow to get a value; values exist in the data, not the column headers. In LINQ, there is an extension method that might help:
string val = table.Rows[rowIndex].Field<string>("GrossPerPop");
or without LINQ:
string val = (string)table.Rows[rowIndex]["GrossPerPop"];
(assuming the data is a string... if not, use ToString())
If you have a DataView rather than a DataTable, then the same works with a DataRowView:
string val = (string)view[rowIndex]["GrossPerPop"];
#Marc Gravell ....
Your answer actually has the answer of this question.
You can access the data from data view as below
string val = (string)DataView[RowIndex][column index or column name in double quotes] ;
// or
string val = DataView[RowIndex][column index or column name in double quotes].toString();
// (I didn't want to opt for boxing / unboxing) Correct me if I have misunderstood.
for anyone in vb.NET:
Dim dv As DataView = yourDatatable.DefaultView
dv.RowFilter ="query " 'ex: "parentid = 1 "
for a in dv
dim str = a("YourColumName") 'for retrive data
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