C # Dynamic Operation DataTable (new row, column, query row, column, etc.)

Method One: Dynamically create a DataTable and add data to it

public void CreateTable ()
{
Create a table
DataTable dt = new DataTable ();

1. Add columns
Dt. Columns.Add ("Name", typeof (String)); Data type is text

2. Adding columns through the column schema
DataColumn age = New DataColumn ("Age", typeof (Int32)); Data type is shaping
DataColumn time = new DataColumn ("Time", typeof (DateTime)); Data type is time
Dt. Columns.Add (age);
Dt. Columns.Add (time);

1. Add Blank lines
DataRow DR1 = dt. NewRow ();
Dt. Rows.Add (DR1);

2. Add Blank Lines
Dt. Rows.Add ();

3. Adding data rows
DataRow DR2 = dt. NewRow ();
Dr2[0] = "Zhang San"; Assigning values by index
DR2[1] = 23;
dr2["Time"] = datetime.now;//Assignment by name
Dt. Rows.Add (DR2);

4. Add by line Frame
Dt. Rows.Add ("John Doe", 25,datetime.now);//add the data order of your parameters corresponds to the column in DT

}

Method Two: Add a new column for an existing datetable, its value can be set to the default value, or the column can be set to not be empty.

public void CreateTable (DataTable vTable)
{
Add a new column to an existing DataTable
DataColumn DC1 = new DataColumn ("Tol", typeof (String));
VTABLE.COLUMNS.ADD (DC1);

Add a new column whose value is the default value
DataColumn DC2 = new DataColumn ("Sex", typeof (String));
DC2. DefaultValue = "male";
DC2. AllowDBNull = false;//This is at the beginning of the table, its role, when added to the existing table column, does not work
VTABLE.COLUMNS.ADD (DC2);
}

Method Three: Filter data in the DataTable, using the Select () method, the results can be saved to datarow[] Drarr; Data, you can save it as a new DataTable

public void selectrowdatatable ()
{
DataTable dt = new DataTable ();//Assuming that DT is a result of "select C1,C2,C3 from T1" Query
for (int i = 0; i < dt. Rows.Count; i++)
{
if (dt. rows[i]["C1"]. ToString () = = "abc")//Query condition
{
To operate
}
}
But this practice with one or two times fortunately, with more tired. Is there a better way to do that? Is dt. Select (), the above operation can be changed to this:

datarow[] Drarr = dt. Select ("c1= ' abc");//query (if all data is queried unconditionally in select)

You can also do this:
datarow[] drArr1 = dt. Select ("C1 like ' abc% '");//Fuzzy query (if the multi-criteria filter, you can add and OR OR)
datarow[] drArr2 = dt. Select ("' abc ' like C1 + '% '", "C2 DESC");//Another method of fuzzy query
datarow[] drArr3 = dt. Select ("c1= ' abc '", "C2 DESC");//Sort

Again, if you want to assign a DataRow to a new DataTable, how do you assign a value? You might think:
DataTable dtNew1 = dt. Clone ();
for (int i = 0; i < drarr.length; i++)
{
DTNEW1.ROWS.ADD (Drarr[i]);
}

But this procedure will be wrong, said the DataRow belongs to other DataTable, how to do it? Very simple, so it can be solved:
DataTable dtNew2 = dt. Clone ();
for (int i = 0; i < drarr.length; i++)
{
Dtnew2.importrow (Drarr[i]);//importrow is a copy.
}
}

Method Four: Filter the specified field to the DataTable and save as a new table

public void selectcolumndatatable (DataTable dt)
{
Filter the specified field to a DataTable and save as a new table
DataTable dtnew = dt. Defaultview.totable (False, new string[] {"Column name", "Column Name", "Column Name"});//These column names, ensure that the DT exists, otherwise it will report an error
}

Method Five: Sort the datatable by setting (sort)

public void sortdatatable (DataTable dt)
{
Dt. Defaultview.sort = "id desc";//Reset Sort
DataTable dtnew = dt. Defaultview.totable (); Save in a new table
}

C # Dynamic Operation DataTable (new row, column, query row, column, etc.)