Yet another way of binding a control to a field name in Visual F#

On my last post, I’ve shown you how to bind a record value to a control using the DataBindings method. Another way of binding a control to a fieldname is by using Text property of a control and assigning the dataset collection properties as its value:

Syntax:

controlobjvariable.Text<- (datasetname.Tables.["tablename"].Rows.Item(rowindexnumber).Item(columnindexnumber))

For instance:

emplabel.Text<-Convert.ToString(dataset11.Tables.["tblEmployee"].Rows.Item(0).Item(0))

The rowindexnumber of the first record on your table is 0, the second record is 1 and so on. Same goes with the columnindexnumber. For a simple example of application that uses the binding method above, follow these steps(I assume here that you have already created a database file named “dbEmployee” and a table named “tblEmployee”):
1. Click Start>All Programs>Microsoft Visual Studio 2008>Microsoft Visual Studio 2008.
2. Click File>New>Project>Select Visual F# in the project types>Select F# application in the Visual Studio installed templates category.
3. Click the Project menu>Add reference>Click the .Net tab>Locate then double-click System.Windows.Forms. Do step 3 again and this time, select System.Drawing and System.Data from the .Net tab.
4. Enter the following code after the line “// Learn more about F# at http://fsharp.net “:

// Learn more about F# at http://fsharp.net
//specifies the memory location of the class files
//that will be needed in our application
open System
open System.Windows.Forms
open System.Data
open System.Drawing
open System.Data.OleDb
//creates a font
let ffont=new Font("Verdana", 9.75F,FontStyle.Regular, GraphicsUnit.Point)  
//creates a connection object
let oleconn = new System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;
  Data Source=C:\Documents and Settings\Administrator\My Documents\dbEmployee.mdb")
 //creates an OleDbDataAdapter
let dataadpter = new System.Data.OleDb.OleDbDataAdapter("Select * from tblEmployee", oleconn)
let deletecommand=new System.Data.OleDb.OleDbCommand()

//generates a dataset
let dataset11 = new DataSet()
//fills the dataset with recod values
dataadpter.Fill(dataset11,"tblEmployee")|>ignore
//creates a form
let dataform = new Form(Text="Bind Form Control Part 2",AutoScaleDimensions=new System.Drawing.SizeF(60.0F, 13.0F),ClientSize=new System.Drawing.Size(300, 200),StartPosition=FormStartPosition.CenterScreen)
//creates our controls
let exitbutton=new Button(Text="Exit", Location=new System.Drawing.Point(190, 170))  
let label1=new Label(Text="Employee number:",Location=new System.Drawing.Point(0, 10),AutoSize=true)
let label2=new Label(Text="Firstname:",Location=new System.Drawing.Point(0, 50),AutoSize=true)
let label3=new Label(Text="Lastname:",Location=new System.Drawing.Point(0,100),AutoSize=true)
let emplabel=new Label(Location=new System.Drawing.Point(140,10),BorderStyle=BorderStyle.FixedSingle)
let fnamelabel=new Label(Location=new System.Drawing.Point(100,50),BorderStyle=BorderStyle.FixedSingle)
let lnamelabel=new Label(Location=new System.Drawing.Point(100,100),BorderStyle=BorderStyle.FixedSingle)
//assings the font to our form
dataform.Font<-ffont
//adds the controls to our form
dataform.Controls.Add(exitbutton)
dataform.Controls.Add(label1)
dataform.Controls.Add(label2)
dataform.Controls.Add(label3)
dataform.Controls.Add(emplabel)
dataform.Controls.Add(fnamelabel)
dataform.Controls.Add(lnamelabel)

//binds the fieldnames to our label
emplabel.Text<-Convert.ToString(dataset11.Tables.["tblEmployee"].Rows.Item(0).Item(0))
fnamelabel.Text<-Convert.ToString(dataset11.Tables.["tblEmployee"].Rows.Item(0).Item(1))
lnamelabel.Text<-Convert.ToString(dataset11.Tables.["tblEmployee"].Rows.Item(0).Item(2))

//when the exit button is clicked
exitbutton.Click.Add(fun exit->
//close the form and dataconnection
                    dataform.Close()
                    oleconn.Close())

//executes our application
dataform.Show()
Application.Run(dataform)

5. This will display the following output:

Manipulating an Image Data in Visual F#

To manipulate an image data, simply add an oleobject fieldname on your table and insert a bitmap image to it. To display the image on your form, use a picturebox control then bind your oleobject fieldname to it using the following syntax:

Pictureboxobjname.DataBindings.Add(new Binding(pictureboxproperty,datasource,fieldname))

For instance:

appico.DataBindings.Add(new Binding("Image",bindingsource,"oleapplogo",true))

The last boolean parameter enables the control formatting. We also use the Image property instead of the usual Text for the fact that it is the property used to display an image on your form.

Before proceding to the steps below, I want you to make an Ms-Access 2003 or 2007 database file named “dbApplication”. Create a table inside it and name it “tblApplication”. Use the following specifications:

Chrappname	Text	Handles the application name
Oleapplogo	OLE Object	Handles the application ico

After creating your table, you can add appropriate values to it for instance:

chrappname	oleapplogo
PHP	Bitmap Image
Apache	Bitmap Image

Bitmap Image refers the the Bitmap Object that you have inserted using the Paste From Ms-Paint command.

After creating the table and adding appropriate values to it.We are now ready for our sample application. Just follow these steps:

1. Click Start>All Programs>Microsoft Visual Studio 2008>Microsoft Visual Studio 2008.

2. Click File>New>Project>Select Visual F# in the project types>Select F# application in the Visual Studio installed templates category.

3. Click the Project menu>Add reference>Click the .Net tab>Locate then double-click System.Windows.Forms. Do step 3 again and this time, select System.Drawing and System.Data from the .Net tab.

4. Enter the following code after the line “// Learn more about F# at http://fsharp.net “:

// Learn more about F# at http://fsharp.net
//specifies the memory location of the class files
//that will be needed in our application
open System
open System.Windows.Forms
open System.Data
open System.Drawing
//creates a font
let ffont=new Font("Verdana", 9.75F,FontStyle.Regular, GraphicsUnit.Point)  
//creates a connection object
let oleconn = new System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;
  Data Source=C:\Documents and Settings\station 2\My Documents\dbApplication.mdb")
 //creates an OleDbDataAdapter
let dataadpter = new System.Data.OleDb.OleDbDataAdapter("Select * from tblApplication", oleconn)
//generates a dataset
let dataset11 = new DataSet()
//fills the dataset with recod values
dataadpter.Fill(dataset11,"tblApplication")|>ignore
//creates a form
let dataform = new Form(Text="Manipulate Image Data",AutoScaleDimensions=new System.Drawing.SizeF(60.0F, 13.0F),ClientSize=new System.Drawing.Size(300, 200),StartPosition=FormStartPosition.CenterScreen)
//creates our controls  
let label1=new Label(Text="App. name:",Location=new System.Drawing.Point(0, 10),AutoSize=true)
let label2=new Label(Text="Icon:",Location=new System.Drawing.Point(0, 50),AutoSize=true)
let appnamelabel=new Label(Location=new System.Drawing.Point(140,10),BorderStyle=BorderStyle.FixedSingle)
let appico=new PictureBox(SizeMode=PictureBoxSizeMode.StretchImage,Location=new System.Drawing.Point(140,50))

let bindingsource=new BindingSource()
//creates a binding navigator
//this will allow us to add navigational buttons to our data grid
let bindingnav=new BindingNavigator(Dock=DockStyle.None,Location=new System.Drawing.Point(100, 170))
//creates a toolstrip buttons for our binding navigator
let movefirst=new ToolStripButton(Text="Top")
let moveprev=new ToolStripButton(Text="Prev")
let movenext=new ToolStripButton(Text="Next")
let movelast=new ToolStripButton(Text="Bottom")
let exitbutton=new ToolStripButton(Text="Exit")
//adds the toolstripbuttons to our binding navigator
bindingnav.Items.Add(movefirst)|>ignore
bindingnav.Items.Add(moveprev)|>ignore
bindingnav.Items.Add(movenext)|>ignore
bindingnav.Items.Add(movelast)|>ignore
bindingnav.Items.Add(exitbutton)|>ignore
//adds a function to each buttons
bindingnav.MoveFirstItem<-movefirst
bindingnav.MoveNextItem<-movenext
bindingnav.MovePreviousItem<-moveprev
bindingnav.MoveLastItem<-movelast
exitbutton.Click.Add(fun exit->
//close the form and dataconnection
                    dataform.Close()
                    oleconn.Close())
//assigns the dataset name as a bindingsource datasource
bindingsource.DataSource<-dataset11
//assigns our table as a binding source datamember
bindingsource.DataMember<-"tblApplication"
//assigns the bindingsource name as a binding navigators
//bindingsource value
bindingnav.BindingSource<-bindingsource
//opens the connection
oleconn.Open()
//assings the font to our form
dataform.Font<-ffont
//adds the controls to our form
dataform.Controls.Add(label1)
dataform.Controls.Add(label2)
dataform.Controls.Add(appnamelabel)
dataform.Controls.Add(appico)

dataform.Controls.Add(bindingnav)
//binds the fieldnames to our label
appnamelabel.DataBindings.Add(new Binding("Text",bindingsource,"chrappname"))
appico.DataBindings.Add(new Binding("Image",bindingsource,"oleapplogo",true))
//executes our application
dataform.Show()
Application.Run(dataform)

5. Click the run icon to execute your application. You should now see an output similar to the following screen shot: 6. Here’s another version of the code above without BindingSource and BindingNavigator.

// Learn more about F# at http://fsharp.net
//specifies the memory location of the class files
//that will be needed in our application
open System
open System.Windows.Forms
open System.Data
open System.Drawing
//creates a font
let ffont=new Font("Verdana", 9.75F,FontStyle.Regular, GraphicsUnit.Point)  
//creates a connection object
let oleconn = new System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;
  Data Source=C:\Documents and Settings\station 2\My Documents\dbApplication.mdb")
 //creates an OleDbDataAdapter
let dataadpter = new System.Data.OleDb.OleDbDataAdapter("Select * from tblApplication", oleconn)
//generates a dataset
let dataset11 = new DataSet()
//fills the dataset with recod values
dataadpter.Fill(dataset11,"tblApplication")|>ignore
//creates a form
let dataform = new Form(Text="Manipulate Image Data",AutoScaleDimensions=new System.Drawing.SizeF(60.0F, 13.0F),ClientSize=new System.Drawing.Size(300, 200),StartPosition=FormStartPosition.CenterScreen)
//creates our controls  
let label1=new Label(Text="App. name:",Location=new System.Drawing.Point(0, 10),AutoSize=true)
let label2=new Label(Text="Icon:",Location=new System.Drawing.Point(0, 50),AutoSize=true)
let appnamelabel=new Label(Location=new System.Drawing.Point(140,10),BorderStyle=BorderStyle.FixedSingle)
let appico=new PictureBox(SizeMode=PictureBoxSizeMode.StretchImage,Location=new System.Drawing.Point(140,50))
//opens the connection
oleconn.Open()
//assings the font to our form
dataform.Font<-ffont
//adds the controls to our form
dataform.Controls.Add(label1)
dataform.Controls.Add(label2)
dataform.Controls.Add(appnamelabel)
dataform.Controls.Add(appico)
//binds the fieldnames to our label
appnamelabel.DataBindings.Add(new Binding("Text",dataset11,"tblApplication.chrappname"))
appico.DataBindings.Add(new Binding("Image",dataset11,"tblApplication.oleapplogo",true))
//executes our application
dataform.Show()
Application.Run(dataform)

For more sketchy tutorials on Visual F# visit Microsoft F# Developer Center.