Все вопросы: [dataset]

382 вопросов

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Converting System.Linq.IorderedEnumerable to DataView

I am trying to get the DataView from a linq query expression which is querying a typed dataset. The result lands in a type of System.linq.IOrderedEnumerable. But i'm not able to convert this type to a Dataview although a few examples on the internet say that AsDataView function shoudl work but co...

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ADO.net - what are the constraints on database connectivity for use of DataSet and DataAdapter?

Re ADO.net, I get the concept generally of DataSet and DataAdapter. What's not clear if I may ask is: Q1 - What constraints are there on whether the database connection need to remain open or not? Can I close the connection but still work with DataSet? If so what needs to be in place to perf...

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96 просмотров

in .net what class(s) should I use to make working with data from DB easy (not including Entity Framework or LINQ)

QUESTION 1 - What .NET classes should I be looking at to help me read / update some data in a database, but assuming I'm not using LINQ or Entity Framework. That is if you drop back to the core .net framework what are the key classes to use. In particular something that lets me access data fr...

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C# - DataSets and Data Binding in multiple Forms

I have the following scenario: A database A DataSet that is filled by the database Two Forms: The first Form contains a ComboBox that shows a certain set of categories. The ComboBox is binded to a DataTable "categories" in the DataSet. The second Form is supposed to be a category manager wher...

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Help with DataAdapter - DB doesn't update?

I have a data adapter. When I check the function at runtime I see the changes, but nothing happens in the database. How do I debug this? What went wrong? OleDbDataAdapter adapter = new OleDbDataAdapter(); string queryString = "SELECT * FROM tasks"; OleDbConnection connection = new OleDbConnectio...

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7849 просмотров

VB.NET Dataset update

I'm new to vb.net and having quite a challenge with updating a field in a table using the For...Next construct on a data set. Sample code below - can anyone tell me what I'm missing? I know this particular example could be accomplished with a simple SQL update statement, but the actual use for ...

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Is there any way for DBUnit to automatically create tables?

I just realized that DBUnit doesn't create tables by itself (see How do I test with DBUnit with plain JDBC and HSQLDB without facing a NoSuchTableException?). Is there any way for DBUnit to automatically create tables from a dataset or dtd? EDIT: For simple testing of an in-memory database lik...

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3ответов
11571 просмотров

gridview paging using dataset

I have an ASP.NET web app (C#) where I get some information from a datasource and display it in the the gridview. I wanted to enable paging, but for some reason, paging doesn't work. I researched a little online, and I found that paging is done differently if a dataset is used. When I click on a ...

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DataSet, an old confusion

When should I use DataSet instead of DataReader? When I must use DataSet instead of DataReader? When should I use data in a disconnected fashion? When I must use data in a disconnected fashion? N.B. I am not asking which is better. I need to know the appropriate scenarios of the use of Data...

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Is the untyped .net DataSet a duck typed DTO?

Okay, I'm accessing the fields of a data row inside a data set using indexers, but let's consider this as just a syntactical feature. Would you go so far and call it a duck typed thing that is reduced to getters and setters, in other words a data transfer object?

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Most efficient way to do an XSL transformation on a DataSet?

What is most efficient way (code example) to do an XSL transformation on a DataSet in .NET 2.0?

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Which tool to use for drawing large scatterplots

For drawing Scatter plots of>100K points, Excel 2007/10 hangs under repeated refresh. What is a better tools for such tasks. I have 4 GB ram etc on this machine.

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Warning in XML Editor on Typed DataSet ".XSC" File

It all about a typed Dataset... The 'urn:schemas-microsoft-com:xml-msdatasource:DataSetUISetting' element is not declared <?xml version="1.0" encoding="utf-8"?> <!--<autogenerated> This code was generated by a tool. Changes to this file may cause incorrect behavior and ...

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LINQ to DataSet case insensitive group by

I have a data table and I want to perform a case insensitive group by over a column of data table (say Column1 of type string). I observed that normally LINQ to DataSet performs a case sensitive comparison. For example, if Column1 has two string values "Test" and "test", after applying group by i...

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13943 просмотров

.Net System.OutOfMemoryException filling a datatable

I need to extract data from a .dbf file and transform it into xml. I wrote a routine that does it just fine. However now we are encountering very large .dbf files - like 2GB +. And this code throws an OutOfMemoryException on those files. Public Function GetData() As DataTable Dim dt As Ne...

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How to display a DataRelation on DataGridView

5 and I try to solve the "more than one entity situation" using a single query for each one and then joined them with DataRelation, so after I realized that I've tryed to show data on this way : DataColumn parentColumn = dataSet.Tables["Suppliers"].Columns["SupplierID"]; DataColumn childColumn ...

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asp.net 2.0: best data structure to bind to gridview

For the most part, the application I'm working on deals with object, and I can bind a list of objects to a gridview without any problems. However, in a couple of cases, I want to display the results of a multi-table join in a gridview. The current code uses a dataset, which is pretty easy, but ...

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DataSet Designer - Auto Add Columns

in my VB.Net application I've created a Dataset that call an existing MS SQL Server stored procedure but after the wizard close no columns where added... how can I add all the columns returned by the stored procedure without adding them manually (off course the stored procedure might change in th...

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put Custom Class Array into a dataset or XML (C#)

I am making a small card game which requires a high score list that is saved to an external file, and loaded from it at the beginning of each each game. I wrote an XML file in this format: <highscore> <name>bob</name> <score>10</score> <time>3:42</time>...

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Passing a large dataset to the client - Javascript arrays or JSON?

I'm passing a table of up to 1000 rows, consisting of name, ID, latitude and longitude values, to the client. The list will then be processed by Javascript and converted to markers on a Google map. I initially planned to do this with JSON, as I want the code to be readable and easy to deal with...

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.Net Linq DataSet Problems (left outer joins)

I have 3 sql tables SourceKeys, Channels, and ChannelTypes. These tables are queried and their data is stored in datatables in my dataset. What I need is this: SELECT ... FROM ChannelTypes ct LEFT OUTER JOIN Channels ch ON ct.channelTypeID = channelTypeID LEFT OUTER JOIN SourceKeys sk ON ch.ch...

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C# : WCF Service with IXMLSerializable member turns into DataSet

.NET I have a web service, one of the data members of a message implements IXmlSerializable, when I do "Add Service Reference" that member becomes a DataSet. I am trying to pass a serialized Expression<TDelegate> as a parameter to the web service. Q: How do I make a DataSet out of the ...

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Need to convert data set to string in C#

Have an Excel data source which I am querying ok and posting data in data grid. The trick is that I want the data in a string variable but am failing to do that. I have tried arrayLists and arrays and I am not getting there yet because dataset has multiple data types (numbers, strings). Please ...

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How to check if it's null?

I retrieve data from database like below. How do I check whether the value retrieved from database is null? Private Function GetBatch() As DataSet Dim dataset As New DataSet Dim adapter As Data.SqlClient.SqlDataAdapter Dim cn As New System.Data.SqlClient.SqlConnection(con...

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Plain, computer parseable lists of common first names?

I need a list of common first names for people, like "Bill", "Gordon", "Jane", etc. Is there some free list of lots of known names, instead of me having to type them out? Something that I can easily parse with the programme to fill in an array for example? I'm not worried about: Knowing if a n...

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1441 просмотров

Building an ORM with Datasets

DataSet is not ORM but it is possible to build an ORM with Dataset http://www.15seconds.com/issue/080103.htm This kind of article is very rare as people seem to oppose Datasets and ORMs so any other example ?

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How do you override a TableAdapter method on a Table in a DataSet?

I currently have a single DataSet declared which contains 3 tables. For sake of this example we will call them User, Question and Answer. On each of these I have a TableAdapter with the various methods required, ie. GetData(), Update(), Delete() etc. On the Answer Table I would like to override...

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3020 просмотров

C# Reordering the Tables in a Dataset

I create a custom dataset that I pass off to a black boxed component. The dataset consists of usually 5-6 tables (with unique names assigned by me). The component takes the dataset and builds a drop down combo box based off the table names. What I am needing to do though is to change the order...

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How do I read in a DataSetName from an XML File using ReadXML() in .Net?

I've written a DataSet to a XML file using .WriteXML(FileName), and the DataSetName property of the dataset is the top-level tag in the file. However, when I try to read the file into a different DataSet using .ReadXML(FileName), the DataSetName isn't changed to the value of the top-level tag. Am...

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C# How to display Dataset's Byte column as an Enum in MS Reporting Services?

How to display an Enumeration Value in Microsoft reporting based on the byte column from a DataTable? I want to cast =Fields!Status.Value to something like (MyEnum)Fields!Status.Value and then call .ToString() on it. Status is a Byte type.