dataset

问题 I have a xml file in my project. I am reading the file through the below code in to combobox cbProduct . The problem is that the cbProduct is displaying duplicate text values. How to make them distinct? I have gone through some links but there way of approach is not related to dataset. I implemented the below code: DataSet ds = new DataSet(); ds.ReadXml(@"..\..\stock.xml"); cbProduct.DataSource = ds.Tables[0]; cbProduct.DisplayMember = "productname"; optional : If you have time it will be

问题 In my application I have a DataSet that holds tables that are used in different forms, all over my application. To be able to maintain concurrency between forms, and not having to get data from the database every time the user opens a new form, I hold my DataSet as a static field in the program class like this: static class Program { public static CustomDataSet StockDataSet { get; private set; } [STAThread] static void Main() { StockDataSet = new Database.CustomDataSet(); StockDataSet

问题 I'm working on a pretty large table, (800k records and climbing) and I'd like to filter said table. The thing is, the table is stored in SQL Server. So, I was wondering, would a SELECT * FROM table WHERE condition1=true query be faster than loading the table to a typed DataSet and using DataRow.Find() then sending all those to another DataTable? I'm guessing yes, but I'll ask anyway. 回答1: As long as your SQL server is not paging because of RAM starvation the SQL Server should always be faster

问题 I have 2 extracted data sets from a dataset called babies2009( 3 vectors count, name, gender ) One is girls2009 containing all the girls and the other boys2009. I want to find out what similar names exist between boys and girls. I tried this common.names = (boys2009$name %in% girls2009$name) When I try babies2009[common.names, ] [1:10, ] all I get is the girl names not the common names. I have confirmed that both data sets indeed contain boys and girls respectively by doing taking a 10 sample

问题 This is similar to this question: Weka Predictions to CSV, but from the command line. I have the following Weka command: java -Xmx10G weka.classifiers.meta.FilteredClassifier \ -t test_data.arff -d prediction.model -p first -no-cv \ -F "weka.filters.unsupervised.attribute.Remove -R 1" \ -W hr.irb.fastRandomForest.FastRandomForest \ -- -I 512 -K 0 -S 512 Which gives me the following data: === Predictions on training data === inst# actual predicted error prediction (primary_key) 1 1:0 1:0 0.996

问题 We have an ASP.Net / VB.Net web form containing a drop down list in the markup of the aspx file. There is also a DataSet created with the DataSet designer. We would like to populate the drop down with data from the DataSet. Can you show me some sample markup and / or VB.Net coding that is required to populate the drop down list with the DataSet data? 回答1: <asp:DropDownList ID="MyDropDownList" runat="server" DataTextField="SomeString" DataValueField="SomeUniqueId" /> Code-behind: protected

问题 I have a TDBLookupComboBox showing a TStringField of kind fkLookup , which allows Null values (from a nullable Integer database column). The dropdown list displays the items from the assigned LookupDataSet , which comes from a joined table. If the field is Null , none of the list items are displayed, the combobox is empty. If the field has a value, the correct description is shown. I can reset it to Null by pressing the assigned NullValueKey . That's all ok, but the users prefer using the

问题 Is there a way to add an index to a datatable in .Net? I have a datatable holding about 1,100 rows and the datatable.select statement seems a bit slow for an in-memory operation. 回答1: table.PrimaryKey = new DataColumn[]{table.Columns("column1"),table.Columns("column2")} when searching table.Rows.Find(New Object(){<value in column1>, <value in column2>}) This will return a datarow. Also the Primary key values must be unique, otherwise an exception will be thrown. 来源： https://stackoverflow.com

问题 This is my first go at trying to create an HDF5 file from scratch using the Low-Level commands via MATLAB. My issue is that I am having a hard time trying to write data to each specific member in the datatype on my dataset. First, I create a new HDF5 file, and set the right layer of groups: new_h5 = H5F.create('new_hdf5_file.h5','H5F_ACC_TRUNC','H5P_DEFAULT','H5P_DEFAULT'); new_h5 = H5G.create(new_h5,'first','H5P_DEFAULT','H5P_DEFAULT','H5P_DEFAULT'); new_h5 = H5G.create(new_h5,'second','H5P

问题 I have gathered a set of transactions in a CSV file of the format: {Pierre, lait, oeuf, beurre, pain} {Paul, mange du pain,jambon, lait} {Jacques, oeuf, va chez la crémière, pain, voiture} I plan to do a simple association rule analysis, but first I want to exclude items from each transactions which do not belong to ReferenceSet = {lait, oeuf, beurre, pain} . Thus my resulting dataset would be, in my example : {Pierre, lait, oeuf, beurre, pain} {Paul,lait} {Jacques, oeuf, pain,} I'm sure this