DataSet Data Filtering

1. Remove duplicate values from DataSet. The effect is similar to that of distinct in SQL. The DefaultView. ToTable method is used.

Code: the implementation function is to retrieve non-repeated values from the "distinct" column in dt

DataTable result = dt.Tables[0].DefaultView.ToTable(true, "jh");

DataView. ToTable method (Boolean, String [])

Create and return a new able Based on the rows in the existing DataView.

Namespace:System. Data

Assembly:System. Data in System. Data. dll) syntax VBC # C ++ F # JScript Printing

Public DataTable ToTable (bool distinct, params string [] columnNames)

Parameters

Distinct

Type: System. Boolean
If true, the returned DataTable will contain rows with different values for all columns. The default value is false.

ColumnNames

Type: System. String []
A string array that contains the list of column names to be included in the returned DataTable. DataTable contains the specified columns in the same order as these columns in the array.

Return Value Type: System. Data. DataTable
A new able instance contains the requested rows and columns.

2. Filter by conditions from DataSet

string strFilter = "jh='" + item + "'";DataRow[] dr = dt.Tables[0].Select(strFilter);

Appendix: DataTable. Select method (String)

Returns an array of all DataRow objects that match the filtering conditions.

Namespace:System. Data

Assembly:System. Data in System. Data. dll) syntax VBC # C ++ F # JScript Printing

Public DataRow [] Select (string filterExpression)

Parameters

FilterExpression

Type: System. String
The condition used to filter rows.

Return Value Type: System. Data. DataRow []
Array of DataRow objects.