DataGrid Tips (2)
------------ How to implement multi-line head
Sometimes I listen to some friends complaining that .NET's DataGrid is not very easy. As far as my personal experience, DataGrid's function is very powerful, which can make us complete a variety of work, but unfortunately, it is not simple enough. I have accumulated some solutions to some problems that I often encountered, and now I summarize them for your reference. One problem that is often encountered is: We hope that the header of DataGrid is multi-line (Figure 1). I have been looking for a solution for a long time I haven't found a solution, and later I thought of the CAPTIONTEXT and CAPTIONFONT attributes of DataGrid. So I would like to draw multiple lines of heads in the display area of CAPTION. The following sample code implements this idea, as shown in Figure 1.
First, you need to write a class to represent the sheet of self-drawn, this class records the display text, icon, and the information belonging to the columns it juropteed.
// Header class public class TopHeaderColumn {public TopHeaderColumn () {this.columnCollection = new ArrayList ();} private string caption; // text header public string Caption {get {return caption;} set {caption = value ;}} private ArrayList columnCollection; // record information pertaining to the columns of the header jurisdiction (the collection by adding to the object) public ArrayList ColumnCollection {get {return this.columnCollection;} set {this.columnCollection = value;} } Private int width; // Width of the header PUBLIC INT WIDTH {GET {Return Width;} set {width = value;}} private image image = null; // Metet Icon PUBLIC Image Image;} set {image = value;}}
} In addition, because the next code requires the location of the DataGrid horizontal scroll bar, and the DataGrid cannot obtain the position of the horizontal scroll bar, so you need to make a little modification to the DataGrid. Public Class MyDataGrid: DataGrid {public scrollbar hscrollbar {get {return this.hizscrollbar;}}} Ok, you can work. Create a new Window application, join a MyDataGrid, SqlConnection, and ImageList, connect the SQL database Northwind. Of course, we have added the above code namespace WindowsApplication1 {public class Form1: System.Windows.Forms.Form {private System.Data.SqlClient.SqlConnection sqlConnection1; private myDataGrid dataGrid1; private ArrayList al; private System.Windows.Forms.ImageList imageList1 // Join this sentence in InitializeComponent (): this.dataGrid1 = new mydataGrid (), and sets other DataGrid properties according to your needs. Note that CaptionVisible must be set to true, captionText = "" ". private void Form1_Load (object sender, System.EventArgs e) {SqlDataAdapter da = new SqlDataAdapter ( "select lastname, firstname, Address, City from employees", this.sqlConnection1); DataSet ds = new DataSet (); da.Fill (ds , "Employees"); this.dataGrid1.datasource = DS; this.DataGrid1.datamember = "EMPLOYEES";
// columns in the DataGrid DataGridTextBoxColumn c1 = new DataGridTextBoxColumn (); DataGridTextBoxColumn c2 = new DataGridTextBoxColumn (); DataGridTextBoxColumn c3 = new DataGridTextBoxColumn (); DataGridTextBoxColumn c4 = new DataGridTextBoxColumn (); c1.MappingName = "lastname"; c2.MappingName = "firstname"; c3.mappingname = "address"; c4.mappingname = "city"; c1.Headertext = "lastname"; c2.Headertext = "firstname"; c3.Headertext = "address; c4.Headertext =" City "; c1.widthchanged = new eventHandler (this.abc); // The width change adjusts the header width c2.widthchanged = new eventhandler (this.abc); c3.widthchanged = new eventhandler (this.abc);c4.WidthChanged = new EventHandler (this.abc); DataGridTableStyle dts = new DataGridTableStyle (); dts.GridColumnStyles.Add (c1); dts.GridColumnStyles.Add (c2); dts.GridColumnStyles.Add (c3); dts.GridColumnStyles .Add (c4);
DTS.MAppingName = "EMPLOYEES"; this.dataGrid1.tablestyles.add (dts);
// Establish a self-drawn head class and add them to the collection al al = new arraylist (); topheaderColumn tc1 = new TopHeaderColumn (); tc1.caption = "name"; tc1.image = this.imagelist1.images [0]; Tc1.columncollection.Add (0); // Record the index tc1.columncollection.add (1) of the column it jurisdiction; tc1.width = c1.width c2.width; TopHeaderColumn TC2 = New TopHeaderColumn (); tc2.caption = "Address"; tc2.columncollection.Add (2); tc2.columncollection.Add (3); tc2.width = c3.width c4.width; al. ADD (TC1); Al.Add (TC2); this .DataGrid1.paint = new system.windows.Forms.PainteventHandler (this.DataGrid1_paint);}
Private void DataGrid1_paint (Object Sender, System.Windows.Forms. Painteventargs E) {INT x = 0; // Calculate the left distance of the first header INT LEFT = this.dataGrid1.tablestyles [0]. RowHeaderwidth-this. DataGrid1.hscrollBar.Value; // Traversing the head collection Al, draws the header Foreach (Object O in this.al) {// calculates the left distance of the header (text center) x = left ((TopHeaderColumn) o) .Width-convert.Toint32 (E.Graphics. MeasureString ((TopHeaderColumn) o) .caption, this.dataGrid1.captionFont). Width)) / 2; // Complete the header Draw IF ((TopHeaderColumn) O ) .Image! = Null) E.Graphics.drawImage ((TopHeaderColumn) o) .image, x-imagelist1.images [0] .size.width, 0); E.Graphics.drawstring ((TopHeaderColumn) O) .Caption, this.dataGrid1. CaptionFont, New Solidbrush (THISDATAGRID1.CAPTIONFORECOLOR), X, 0); IF (x> 0) E.Graphics.drawline (New Pen (Color.Black, 2), Left-1, 0, Left-1, this.DataGrid1.Height; // Calculate the left distance of the next header Left = ((TopHeaderColumn) o) .width;} if (x Private Void ABC (Object Sender, Eventargs E) {// Sets the width of the header foreach (Object O in this.al) {(TopHeaderColumn) o) .width = 0; Foreach (INT I in (TopHeaderColumn) O) .ColumnCollection) {((TopHeaderColumn) o) .Width = this.dataGrid1.TableStyles [0] .GridColumnStyles [i] .Width;}}} private void dataGrid1_Scroll (object sender, System.EventArgs e) {this.dataGrid1.Refresh (); The above code implements two-layer header, as for the three-layer header. About how to implement a DataGrid multi-layer header, many netizens mentioned that there is no particularly convenient way. If the netizen discovers a better way, please leave a short train to inform me, thank you.
