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:

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  1. controlobjvariable.Text<- (datasetname.Tables.["tablename"].Rows.Item(rowindexnumber).Item(columnindexnumber))  
For instance:
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  1. 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 “:
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  1. // Learn more about F# at http://fsharp.net  
  2. //specifies the memory location of the class files  
  3. //that will be needed in our application  
  4. open System  
  5. open System.Windows.Forms  
  6. open System.Data  
  7. open System.Drawing  
  8. open System.Data.OleDb  
  9. //creates a font  
  10. let ffont=new Font("Verdana", 9.75F,FontStyle.Regular, GraphicsUnit.Point)    
  11. //creates a connection object  
  12. let oleconn = new System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;  
  13.   Data Source=C:\Documents and Settings\Administrator\My Documents\dbEmployee.mdb")  
  14.  //creates an OleDbDataAdapter  
  15. let dataadpter = new System.Data.OleDb.OleDbDataAdapter("Select * from tblEmployee", oleconn)  
  16. let deletecommand=new System.Data.OleDb.OleDbCommand()  
  17.   
  18. //generates a dataset  
  19. let dataset11 = new DataSet()  
  20. //fills the dataset with recod values  
  21. dataadpter.Fill(dataset11,"tblEmployee")|>ignore  
  22. //creates a form  
  23. 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)  
  24. //creates our controls  
  25. let exitbutton=new Button(Text="Exit", Location=new System.Drawing.Point(190, 170))    
  26. let label1=new Label(Text="Employee number:",Location=new System.Drawing.Point(0, 10),AutoSize=true)  
  27. let label2=new Label(Text="Firstname:",Location=new System.Drawing.Point(0, 50),AutoSize=true)  
  28. let label3=new Label(Text="Lastname:",Location=new System.Drawing.Point(0,100),AutoSize=true)  
  29. let emplabel=new Label(Location=new System.Drawing.Point(140,10),BorderStyle=BorderStyle.FixedSingle)  
  30. let fnamelabel=new Label(Location=new System.Drawing.Point(100,50),BorderStyle=BorderStyle.FixedSingle)  
  31. let lnamelabel=new Label(Location=new System.Drawing.Point(100,100),BorderStyle=BorderStyle.FixedSingle)  
  32. //assings the font to our form  
  33. dataform.Font<-ffont  
  34. //adds the controls to our form  
  35. dataform.Controls.Add(exitbutton)  
  36. dataform.Controls.Add(label1)  
  37. dataform.Controls.Add(label2)  
  38. dataform.Controls.Add(label3)  
  39. dataform.Controls.Add(emplabel)  
  40. dataform.Controls.Add(fnamelabel)  
  41. dataform.Controls.Add(lnamelabel)  
  42.   
  43. //binds the fieldnames to our label  
  44. emplabel.Text<-Convert.ToString(dataset11.Tables.["tblEmployee"].Rows.Item(0).Item(0))  
  45. fnamelabel.Text<-Convert.ToString(dataset11.Tables.["tblEmployee"].Rows.Item(0).Item(1))  
  46. lnamelabel.Text<-Convert.ToString(dataset11.Tables.["tblEmployee"].Rows.Item(0).Item(2))  
  47.   
  48. //when the exit button is clicked  
  49. exitbutton.Click.Add(fun exit->  
  50. //close the form and dataconnection  
  51.                     dataform.Close()  
  52.                     oleconn.Close())  
  53.   
  54. //executes our application  
  55. dataform.Show()  
  56. Application.Run(dataform)  
5. This will display the following output:
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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:
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  1. Pictureboxobjname.DataBindings.Add(new Binding(pictureboxproperty,datasource,fieldname))  
For instance:
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  1. 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 “:

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  1. // Learn more about F# at http://fsharp.net  
  2. //specifies the memory location of the class files  
  3. //that will be needed in our application  
  4. open System  
  5. open System.Windows.Forms  
  6. open System.Data  
  7. open System.Drawing  
  8. //creates a font  
  9. let ffont=new Font("Verdana", 9.75F,FontStyle.Regular, GraphicsUnit.Point)    
  10. //creates a connection object  
  11. let oleconn = new System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;  
  12.   Data Source=C:\Documents and Settings\station 2\My Documents\dbApplication.mdb")  
  13.  //creates an OleDbDataAdapter  
  14. let dataadpter = new System.Data.OleDb.OleDbDataAdapter("Select * from tblApplication", oleconn)  
  15. //generates a dataset  
  16. let dataset11 = new DataSet()  
  17. //fills the dataset with recod values  
  18. dataadpter.Fill(dataset11,"tblApplication")|>ignore  
  19. //creates a form  
  20. 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)  
  21. //creates our controls    
  22. let label1=new Label(Text="App. name:",Location=new System.Drawing.Point(0, 10),AutoSize=true)  
  23. let label2=new Label(Text="Icon:",Location=new System.Drawing.Point(0, 50),AutoSize=true)  
  24. let appnamelabel=new Label(Location=new System.Drawing.Point(140,10),BorderStyle=BorderStyle.FixedSingle)  
  25. let appico=new PictureBox(SizeMode=PictureBoxSizeMode.StretchImage,Location=new System.Drawing.Point(140,50))  
  26.   
  27. let bindingsource=new BindingSource()  
  28. //creates a binding navigator  
  29. //this will allow us to add navigational buttons to our data grid  
  30. let bindingnav=new BindingNavigator(Dock=DockStyle.None,Location=new System.Drawing.Point(100, 170))  
  31. //creates a toolstrip buttons for our binding navigator  
  32. let movefirst=new ToolStripButton(Text="Top")  
  33. let moveprev=new ToolStripButton(Text="Prev")  
  34. let movenext=new ToolStripButton(Text="Next")  
  35. let movelast=new ToolStripButton(Text="Bottom")  
  36. let exitbutton=new ToolStripButton(Text="Exit")  
  37. //adds the toolstripbuttons to our binding navigator  
  38. bindingnav.Items.Add(movefirst)|>ignore  
  39. bindingnav.Items.Add(moveprev)|>ignore  
  40. bindingnav.Items.Add(movenext)|>ignore  
  41. bindingnav.Items.Add(movelast)|>ignore  
  42. bindingnav.Items.Add(exitbutton)|>ignore  
  43. //adds a function to each buttons  
  44. bindingnav.MoveFirstItem<-movefirst  
  45. bindingnav.MoveNextItem<-movenext  
  46. bindingnav.MovePreviousItem<-moveprev  
  47. bindingnav.MoveLastItem<-movelast  
  48. exitbutton.Click.Add(fun exit->  
  49. //close the form and dataconnection  
  50.                     dataform.Close()  
  51.                     oleconn.Close())  
  52. //assigns the dataset name as a bindingsource datasource  
  53. bindingsource.DataSource<-dataset11  
  54. //assigns our table as a binding source datamember  
  55. bindingsource.DataMember<-"tblApplication"  
  56. //assigns the bindingsource name as a binding navigators  
  57. //bindingsource value  
  58. bindingnav.BindingSource<-bindingsource  
  59. //opens the connection  
  60. oleconn.Open()  
  61. //assings the font to our form  
  62. dataform.Font<-ffont  
  63. //adds the controls to our form  
  64. dataform.Controls.Add(label1)  
  65. dataform.Controls.Add(label2)  
  66. dataform.Controls.Add(appnamelabel)  
  67. dataform.Controls.Add(appico)  
  68.   
  69. dataform.Controls.Add(bindingnav)  
  70. //binds the fieldnames to our label  
  71. appnamelabel.DataBindings.Add(new Binding("Text",bindingsource,"chrappname"))  
  72. appico.DataBindings.Add(new Binding("Image",bindingsource,"oleapplogo",true))  
  73. //executes our application  
  74. dataform.Show()  
  75. 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.
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  1. // Learn more about F# at http://fsharp.net  
  2. //specifies the memory location of the class files  
  3. //that will be needed in our application  
  4. open System  
  5. open System.Windows.Forms  
  6. open System.Data  
  7. open System.Drawing  
  8. //creates a font  
  9. let ffont=new Font("Verdana", 9.75F,FontStyle.Regular, GraphicsUnit.Point)    
  10. //creates a connection object  
  11. let oleconn = new System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;  
  12.   Data Source=C:\Documents and Settings\station 2\My Documents\dbApplication.mdb")  
  13.  //creates an OleDbDataAdapter  
  14. let dataadpter = new System.Data.OleDb.OleDbDataAdapter("Select * from tblApplication", oleconn)  
  15. //generates a dataset  
  16. let dataset11 = new DataSet()  
  17. //fills the dataset with recod values  
  18. dataadpter.Fill(dataset11,"tblApplication")|>ignore  
  19. //creates a form  
  20. 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)  
  21. //creates our controls    
  22. let label1=new Label(Text="App. name:",Location=new System.Drawing.Point(0, 10),AutoSize=true)  
  23. let label2=new Label(Text="Icon:",Location=new System.Drawing.Point(0, 50),AutoSize=true)  
  24. let appnamelabel=new Label(Location=new System.Drawing.Point(140,10),BorderStyle=BorderStyle.FixedSingle)  
  25. let appico=new PictureBox(SizeMode=PictureBoxSizeMode.StretchImage,Location=new System.Drawing.Point(140,50))  
  26. //opens the connection  
  27. oleconn.Open()  
  28. //assings the font to our form  
  29. dataform.Font<-ffont  
  30. //adds the controls to our form  
  31. dataform.Controls.Add(label1)  
  32. dataform.Controls.Add(label2)  
  33. dataform.Controls.Add(appnamelabel)  
  34. dataform.Controls.Add(appico)  
  35. //binds the fieldnames to our label  
  36. appnamelabel.DataBindings.Add(new Binding("Text",dataset11,"tblApplication.chrappname"))  
  37. appico.DataBindings.Add(new Binding("Image",dataset11,"tblApplication.oleapplogo",true))  
  38. //executes our application  
  39. dataform.Show()  
  40. Application.Run(dataform)  
For more sketchy tutorials on Visual F# visit Microsoft F# Developer Center.
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