1. First quote DocumentFormat.OpenXml.dll2. Then create a new Openexcelhelper class to convert Excel to a DataTable. Organize a DataTable according to the specified Excel streampublic static DataTable Getexceldata (string sheetname, String stream){using (spreadsheetdocument document = Spreadsheetdocument.open (stream, false)){Open Excelienumerableif (sheets. Coun
1. Execute datatable.select ("conditions") in the DataTable to return to the DataTable;Executing a query in a DataTable returns a new DataTableDT is the source data DataTableCondition is a query conditionDataTable NEWDT = new DataTable ();NEWDT = dt. Clone (); Cloning DT structure, including all DT architectures and co
When writing code in the morning, a problem occurs. Use able. Select ("filter condition") to filter data and then pay it to another datatable. An error occurred while running the result. The error message is as follows:Databinding: "system. Data. datarowview" does not contain the attribute "cityname.
Error Code
Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->Public class virtualdata
{
Public virtuald
9-non-connection mode of ADO. NET, DataSet in memory, DataTable --- ShinePans,
DataSet is called a DataSet. It can be compared to a database in memory. DataSet is ADO. NET core, supports ADO.. NET disconnected. The core object of the distributed data solution is also the core component for non-connection-based data query.
Common attributes of DataTable:
Attribute
Description
Columns
Sample I:
I created a public method called linqtodatatable as following:
Public datatable linqtodatatable {Datatable dtreturn = new datatable ();// Column namesPropertyinfo [] oprops = NULL;
If (varlist = NULL) return dtreturn;
foreach (t rec in varlist) { will follow If (oprops = NULL) { foreach (propertyinfo PI in oprops) {
If (coltype. isgenerictype)
private int getcount () {datatable dt /// known datadable, with tens of thousands of records datatable newdt = DT. defaultview. totable ( true , " city " ); int num = newdt. rows. count; return num ;}
datatable sourcetable = New soursetable (); sourcetable. columns. add ( " Code " , string ); /// ... add data to soursetable datav
Code
Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--> /// /// Returns the datatable after the select distinct operation. /// /// Source data table /// Field set /// Private Datatable selectdistinct (datatable sourcetable, Params String [] Fieldnames){ Object [
Datatable converts the data into Json and puts the Json data into the js file. datatablejson
5 code instances in C # converting Datatable to Json
///
// Query the province name var SQL = "select top 35 locid, locname, parentid from location where loctype = 1"; var dt_pro = SQLHelper. get_DataTable (SQL, SQLHelper. getCon (), new Dictionary
For example, enter var cn_pro = [{"locid": 1, "locname": "Be
Generics listFirst we have to take out the DataTable in the dataset, the dataset belongs to the DataTable collection, through the index or tablename can take out the DataTable, the DataTable has more than one column is the table in the database field, To map the attribute variables in the entity class, we assign values
Example of Self-deletion (drTemp is a table and gvSummary is dev's gridview. Right-click grid to delete ):
1. dtTemp. Rows. RemoveAt (gvSummary. FocusedRowHandle );
2. dtTemp. Rows [gvSummary. FocusedRowHandle]. Delete (); dtTemp. AcceptChanges ();
In C #, if you want to delete a row in the DataTable, there are several methods:
1. if you only want to delete a row in the datatable, you can use the delete Sta
Here is a small example of converting an entity class to a DataTable:Use of reflective knowledge.Using System;Using System.Collections.Generic;Using System.Data;Using System.Linq;Using System.Reflection;Using System.Text;Using System.Threading.Tasks;Namespace Net_consoleapplication{Class Program{static void Main (string[] args){User user = new user ();User. Name = "Zhang San";User. Age = 12;User. Birthday = Datetime.today;DataTable dt = setdata}Get ta
) of the datarow initialized by datatable. newrow () is detachedDatarowYesDatarowcollection. Add () is a unique accepted parameter.
Can I use datatable. Copy?
Dteng = dtchi. Copy ();
The answer is:No. The datatable. Copy () method copies the structure and data, which leads to the same column names of the two tables. Here we only need to copy the data.
Description of use of the DataTable: Http://www.dotnetperls.com/datatableSQL results stored in the DataTable example: Http://stackoverflow.com/questions/6073382/read-sql-table-into-c-sharp-datatableBrief code example: String constr = @ "server=stcvm-130;integrated security=true;database=raadb"; SqlConnection con = new SqlConnection (CONSTR); SqlParameter catname = new SqlPar
Tags: normal eve using the cut final values content logical execThis article describes in an instance the three implementation methods for updating a database using the DataSet DataTable, including the CommandBuilder method, DataAdapter updating the data source, and updating using SQL statements. Share it for everyone's reference. Here's how:I. Conditional CommandBuilder method for automatically generating commandsA) dynamically specify SelectCommand
Tags: ADO database DataSetDatasets are referred to as datasets, which can be compared to in-memory databases, the dataset is the core of ADO, and the core object of the Distributed data scheme is to implement the core component of the data query based on the non-connection.DataTable Common Properties:
Property
Description
Columns
Gets the collection of columns that belong to the table
Rows
Gets the collection of rows that belong to the
C # transforms a DataTable into a listWhen using a three-tier architecture to develop a Web site, I want to convert the DataTable object to a ListIdeas:
Initializes a List
Gets all properties to T, Initializes a T object
Traverse all attributes, if the value of the corresponding attribute in the DataTable is assigned to the T object, if there is
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