I would like to select some columns from a Datatable, I mean, something like Select Name, Surname, ID,
I'm trying to do something like this:
DataTable dtExcel = new DataTable();
DataRow[] buena = dtExcel.Select("NAME");
in order to get only a view or table with one column (NAME).
I have an application which was recently ported from Classic ASP to .NET 3.5. I'm pulling some data from a stored procedure and once retrieved, I'm doing using the Select method on the DataTable in a loop so I don't have to keep going back to the database.It appears that there's something wrong here as I can refresh the page repeatedly and see the memory usage increase by a few megabytes, up to the point where we get an error. If we recycle the app pool in IIS, it starts working again, for a little while.
Is there a memory leak in this method? I did some research on the subject and Microsoft said there was an issue like that in .NET 1.0 and 1.1, but I'm using a higher version.Or, is this something else, such as not managing resources correctly? Here's a snipped of my code:
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Initially, this app was using XML instead of a datatable and using XPATH to query the data, but it was too slow. I thought using a dataset with DataTable selects was a better option, but now we found this issue. I was thinking since the loop executes several hundred times that getting all the data and filtering through it on the client was a better choice instead of calling several web methods to get the subsets of data.
I am trying to do something I thought would be simple but something isn't working for me.
I have a DataTable that I need to sort by a price ascending, then select an 'nth' row value. The 'nth' value is the row count/10.
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What happens is I get the "nth" value from the original tblDeals.
i have two sqldatasource controls. one i use to display data in textbox's ,filter'd by a select parameter in page behind code. Once checked, i want to copy this data to the other datasource ,by selecting checkbox.Then display this data in detailsview control.
At present the two datasource controls declared , render data to the page simultaneously during pageload. I want to first check data in textbox's from first source, before second datasource is rendered to screen. note, both are filtered by a page variable. i wish to leave the textbox datasource control in situ, as other controls and code depend on it.The other detailsview datasource is my problem?
The drop down list is used to determine what search criteria will be used to find an invoice. I tried to set the Select method in the switch statement. I don't understand how to set the Select Method and the select parameters programmatically though . I tried a few different ways but can't make the compiler happy. My ODS is in scope in the code behind. I'm not able to access it's properties though. The BAL resides in a separate project that is a ClassLibrary. I also have a using statement for the ClassLibrary project in the code behind.
give me an example of how to do this?
Mark up:
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protected void Button19_Click(object sender, EventArgs e)
{
SqlDataSource conn = new SqlDataSource();
conn.ConnectionString = ConfigurationManager.ConnectionStrings["Database2ConnectionString1"].ToString();
conn.SelectCommandType = SqlDataSourceCommandType.Text;
conn.SelectCommand = "SELECT FROM table1 (a, b)VALUES(@a,@b)";
conn.SelectParameters.Add("a",TextBox1.Text);
conn.SelectParameters.Add("b", TextBox2.Text);
int rowsAffected = 0;
try
{
rowsAffected = conn.Selectt();
}
catch (Exception)
{
Label1.Text = "Error";
}
finally {
conn = null;
}
if (rowsAffected != 0)
{
Label1.Text = "Data saved";
}
}
well it returns error no overloading method for select (P.S. same code work fine for insert)
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Refer to datatable columns with database column names?
How can I get common columns from two intersecting datatable inside dataset?
View 2 RepliesI have a little problem with a DataTable.
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The values are number but varchar, for example '100', '73', '87'. When i see the data this return 100, 87, 73, when should by 73, 87, 100 how can i sort the data????
If I have a linq statement like:
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There may be a lot of data in the Blogs table. What if all I wanted was say BlogID, BlogTitle and BlogAuthor and nothing else, is there a way to do this in an effort to make the sql more efficent?
Along the same lines in my DataContext (.dbml) file I added some associations between some of my tables. This makes coding nice when I do a linq statement that will join those tables automatically for me but my concern is does it do that everytime, thus making all my linq quieries inefficient?
I'm trying to add new rows to a data table and then use the sqldataadapter update method bu fund some problems. First, I written this code:
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Excuse me but the most part of variable are in italian, however I think it is possible to understand how does it work. If I execute this code I obtain this error:
System.InvalidOperationException: Update requires a valid InsertCommand when passed DataRow collection with new rows.
After this I added these lines of code just above the last line:
SqlCommandBuilder cb = new SqlCommandBuilder(adapter);
adapter.InsertCommand = cb.GetInsertCommand;
and I obtained this error:
Cannot convert method group 'GetInsertCommand' to non-delegate type 'System.Data.SqlClient.SqlCommand'. Did you intend to invoke the method?
When using the DataTable.Load(SQLDataReader) method, if the datatable is a property of a class, the set method is not called to populate the object. For example...
MySQLDataReader = command.ExecuteReader();
if (MySQLDataReader.HasRows)
myObjDataTable.Load(MySQLDataReader); -- The result of this will be 0 rows returned. The "Set" method of the object is never called.
How do I select multiple columns into IQueryable<Employee>?
View 2 RepliesIs there a way to do a
"select * as"
and rename all columns with some prefix, rather than having to name columns individually? Or better yet, when doing a join and getting all columns from both tables, how do you identify them uniquely in the VB where some columns have the same name?
it is apparent that "string builder" is better for building large string compared to sMyString = sMyString + "something";
what is a better way to search large in memory datasets? (like the example above - i know i could use loops, is there another way that i dont now about?)
there are multiple rows with same SubContact_No and with same value of some columns. for a single column I am firing query like
Select distinct (Financial_Status) from mtblSub_Contract where SubContract_No=@SubContract_No";
it's working fine.... (it's ok with a Single column)
But Now I need multiple columns value so how to query for this.
Select distinct (Financial_Status, colums2, column3) from mtblSub_Contract where SubContract_No=@SubContract_No"; is not working
So how to do that.
This question is for wrapping up work on a database driven AJAX AutoComplete Control that I am using to provide keyword hints to user on search pages. Each record has 6 columns for keywords where each column is for an advertiser to add a keyword. These are used in meta keywords tags, but I also want to use them for AutoComplete. The problem is that I don't know how to write a SELECT statement in Visual Studio that treats all 6 keyword columns as if they were all one column. I am looking for something like
SELECT (keyword1 + keyword2 + keyword3) AS Keywords
FROM (Merchandise)
WHERE Keywords LIKE @term
The only other thing I can think of the gain this level of functionality would be to combine them into a new table.
i have DateFrom and DateTo columns in tblLOgs.if they both are same then select only DateFrom else both selects.my procedure is ....do modification in them
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I want use select * from sample (tablename) ,which returns only those columns from sample table which does not have xml data type.
note : sample table contains some columns which have xml data type .
i have this class
class MyDal
{
IList<MyData> GetAll(string orderBy, , int count, int firstIndex, out int totalRowCount);
}
i'm using an objectdatasource with MyDal to bind values to a gridview.
i want know if there's a way to configure the objectdatasource to use the parameter totalRowCount without calling the SelectCountMethod.
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The GetList method is as folllowing:
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Now i can populate my gridview trough code by this: //gvwDiensten.DataSource = new BindingList<diensten>(dataManager.GetList<diensten>().ToList());But i would like to use an objectdatasource, so i created this:
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</asp:ObjectDataSource>
But when running the page i get:
ObjectDataSource 'dsDiensten' could not find a non-generic method 'GetList' that has no parameters.
I am having problem with calculated columns in the following code
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orderDT is the DataTable. When "Extra" column has nothing (I am NOT using Default), "Total" comes out to be blank? "Price" will have a value (always) "Extra" may not have any value
Stack-Overflow :3 I've got a kind of hard-case question.
So I'll try clearly explain my idea with my poor english :/ need select to DataTable SOME values from ???_**GetDisplayData **procedure for each day of previos month (GROUP IT) where group rules for different columns is different
I need to select some values in stored procedure from other stored procedure like this :
SELECT X FROM Y_Procedure(@ProcedureParameters)Also I need to select from dynamic SQL Procedure like
Y_Procedure=@Y+'_Procedure'
SELECT X FROM Y_Procedure(@ProcedureParameters)
Also I need to load it to DataTable :-/INSERT INTO @Report (CellHorizontal, CellVertical, CellValue) --to TABLE
SELECT Date,X2,X3 FROM Y_GetDisplayData(@Param)
SET NOCOUNT OFF;
SELECT *
FROM @Report
GetDisplayData works as select with parameters and that doesn't returns SQL DataTable
And there is no way to recode GetDisplayData's procedures, it's just constant procedures for me.Finally I need to Group nodes from this table
INSERT INTO @Report (CellHorizontal, CellVertical, CellValue)
SELECT T1.Date,
IF ((Select grouptype...)=1) T1.X2 + T2.X2
ELSE IF ((Select grouptype...)=2) AVG(T1.X2,T2.X2),
IF ((Select grouptype...)=1) T1.X3 + T2.X3
ELSE IF ((Select grouptype...)=2) AVG(T1.X3,T2.X3),
(SELECT T2.Date,X2,X3 FROM Y_GetDisplayData(@Param) T2
WHERE T2.Date>T1.Date AND T2.Date>=T1.Date)
FROM Y_GetDisplayData(@Param) T1
GROUP BY EVERY DAY ???--and here is epic fail
I can make all stuff on asp server :And C# allows me to use something like SelectCommand = IzmProc + "_GetDisplayData"; And then I will work (select special data) with DataTables on ASP.NET Server but it's better to make all on SQL ... But looking like it's just unrealizable on SQL >_<
I gonna think about C# realization,but my code is very weird , got errors and doesn't works >_<
public static DataTable GetReport(string Param)
{
System.Configuration.ConnectionStringSettings connSetting = ConfigurationManager.ConnectionStrings["FlowServerConnectionString"]; [code].....
I'm implementing a BLL layer and have a few questions. First, in my DAL, there is a contacts table, the select method is a sql query against a sql server 2000 database. The preview data returns everyting as expected. The query is
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The BLL method is built like so
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When using the BLL method to a gridview, the results of the subquery are not displayed. There are also other methods, each having a different where clause for ContactRole_ID and each is having the same issue of not displaying the subquery reult in the gridview. No error, but no data is displayed for the subquery either. Here is the templatefield of the gridview
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Another item that is causing an error is in trying to update a record. Here is the DAL update method
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And the BLL update method
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The error says i have extra parameters, but have no clue where the extra parameters are being picked up. The error isObjectDataSource 'odsContacts' could not find a non-generic method 'UpdateContact' that has parameters: _ContactID, _Active, _ContactName, _Office, _VirtualOffice, _Pager, _Fax, _Home, _Cellular, _Email, _ContactRole_ID, Active, ContactRole_ID, ContactName, Office, Email, VirtualOffice, Pager, FAX, Home, Cellular.And the objectdatasource
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I have one big DataTable with X rows. I want to select Y rows from it and bind them to a new ViewList. While doing it, I want to delete these rows from the DataTable (Having X - Y rows).
What is the best and fast way to do it?
I don't know if it is better to create a new DataTable to have the Y and after that bind them to a ViewList or something else?
I'm also looking for example in code how to select/delete rows from DataTable.