I'm a newbie in VB form programming. I got a task today, it seems so hard for me. basically, I have 2 forms named: Form1 and Form2. Form1 use for management info of students such as: student's code, name, phone number, etc..i have a button in Form1, when I press it, Form2 will be invoked. i have completed it.
the problem is: in Form2, I just have 1 textbox and 1 listbox. how should it work? => when I type in textbox with 1 keyword relate to info of students in Form1, Listbox will display automatically all of students's name that relate to the keyword I typed . I didn't know any idea to do it automatically. anyone can help me please give me a way. Thanks you so much.
Based on the solution which you use to store list of students there could be different possible solutions. But for all of them, using TextChanged event of that TextBox you can set the filter for the main list which contains students.
If you use a DataTable to store students, you can use DefaultView.RowFilter of the DataTable:
dt.DefaultView.RowFilter = string.Format("Name Like '{0}*'", TextBox1.Text)
Also if you are using generic lists for storing students, you can use linq to do so:
var data = list.Where(Function(s) s.Name.StartsWith(x.Name.StartsWith(TextBox1.Text)) _
.ToList()
listBox1.DataSource = New BindingList(Of Student)(data)
Also if interaction between forms was an issue for you, take a look at this post.
Related
I am struggling to find an answer on this;
I have Form1 which contains a databound DataGridView table from a dataSet from a SQL server. Upon double click event of the row, I need to open Form2 to that databound specific ID. Now I understand that I can get each of the columns and loop through all the textboxes and add them in, but these seems very cumbersome and open to mistakes when there could be a large number of individual textboxes.
Instead I just want to open that form to the specific selected record. Something similar to how you could do with MS access...
DoCmd.OpenForm "Form2", , , "ID = " & recordID
Thank you very much for your help #Jimi. I used your solution by creating a new tableAdpter and adding a parameter which is passed to the new form, works perfectly.
I have a DataTable in my DataSet which is not bound to any table in the SQL Database since I need it only inside 2 forms. When I update it in Form1, it works just fine, the table is populated and I can see the data inside a DataGridView (here is the code I use for updating it):
Dim newProcesRow As DataRow = Me.SampleDataSet.Tables("TableSample").NewRow()
newProcesRow("Col1") = val1.ToString()
newProcesRow("Col2") = val2.ToString()
newProcesRow("Col3") = val3.ToString()
Me.Sample_DataSet.Tables("TableSample").Rows.Add(newProcesRow)
After doing this, the DataGridView in Form1 shows the entire table with no problems. After the user clicks a button, Form2 is shown, where there is a DataGridView as well with the same DataSource as the grid in the first form, the unbound table from the DataSet. I also tryed putting a MessageBox in Form2 to return the number of rows from the DataTable and the result was 0.
Is there any way I could make Form2 see the rows in the DataTable without binding it to the database? (I don't want to do unnecessary changes to the DataBase...) Or are there any saves/changes/updates I am not doing to the DataTable?
If there is anything else I should mention in order to make it easier to find a solution, tell me and I will add. Thanks in advance for any piece of advice, have a nice day! (:
I would really appreciate your advice on the following:
I'm working on Windows forms using VB.NET (even though the language is irrelevant to the question at hand).
I've got a main form and wish to call out another one, however depending on a given variable I need the text on some of the new form's elements to change as well as disable some of its controls.
There are two ways I see of doing it:
Send a parameter from the main form and have some logic on the second form to deal with everything on load.
Main Form:
dim newform as new frmcalculate(byval type as string)
New Form:
public sub getexplanation(byval type as string)
select type
case "Sum"
lblexplanation.text = "this is a sum"
case "Subtraction"
lblexplanation.text = "this is a subtraction"
End sub
Set exactly what I want on the main form before calling the new form.
i.e:
dim newform as new frmcalculate()
newform.lblexplanation.text = "This is a sum"
I hope I've managed to explain it correctly.
I'm still new at this especially getting the formats right on Stackoverflow.
In the first approach the code is best managed and organized for further editing. So each form has it own code.
It is not best practice to use second approach. (Editing a form designer from another one)
I have around 15 comboboxes on my form, all being loaded with the same information pulled from a table(~150 entries). Currently I am taking the information from the table, then looping through the entries and adding them to each textbox. I'm wondering if there's a more efficient way to load these comboboxes then having to individually add the table entry into each combobox, having to list 15 lines of code within the For loop.
I'm not seeing any performance issues with this, but figured I might as well work with the most efficient way possible rather than stick with what works. :)
You can create a list of the combo boxes, and then just loop through them. For instance:
Dim cbos() As ComboBox = {ComboBox1, ComboBox2, ComboBox3}
For Each cbo As ComboBox In cbos
' Load cbo from table
Next
Alternatively, if they are named consistently, you could find the combo box by name:
For i As Integer = 1 to 15
Dim cbo As ComboBox = DirectCast(Controls("ComboBox" & i.ToString())), ComboBox)
' Load cbo from table
Next
Since Combobox items are a collection, if their elements are the same, you can build and array with the objects you want to insert, and then just insert this array to each ComboBox with the method AddRange() (it's a method which exists inside the Combobox.items).
Getting an example from MSDN:
Dim installs() As String = New String() {"Typical", "Compact", "Custom"}
ComboBox1.Items.AddRange(installs)
Then you would only have to do a loop to add the array to each ComboBox. Of course, you will need to build your array first on your own, instead of this easy string array from the example.
Reference:
MSDN - AddRange
You could also do it this way since you mentioned that you already have a table.
Use a datatable
Change your table object into a datatable, which will assist in binding to the comboboxes. It might help if you add the datatable to a dataset too. That way you can attach all ComboBoxes (which are UI elements that let users see information) to the same DataSource, which is the datatable, in the dataset.
Binding
Now all you need to do is loop through all the comboboxes and set the datasource to the same table, that is if you decide to do it programmatically like so:
ComboBox1.DataSource = ds.Tables(0)
ComboBox1.ValueMember = "au_id"
ComboBox1.DisplayMember = "au_lname"
A further tutorial on this with the example above is found here
You can then also get the user selected value with ComboBox1.selectedValue.
On the other hand, if you did this with C# WPF, you can bind each comboBox in the XAML directly, I am unsure if this can be done in VB.net as I tried to look for the option but did not manage to do so, something you might want to try though.
Some very useful tutorials and guides on Data binding, which you might be interested:
~ denotes recommended reading for your question
MSDN: Connect data to objects
DotNetPerls on DataGridView (note this isn't a combobox, just displaying values)
~ VBNet DataTable Usage from DotNetPerls (this is in relation to 1.)
~ SO Q&A on Binding a comboBox to a datasource
Concepts of Databinding
I have a simple VB.NET 2008 app that helps users to edit fields in the database. Simple enough as a first "real" project in .NET, right?
For one table, I am currently using a DataGridView so it can be edited straight up. However, instead of offering the user the entire table, I'd like to group the data by the 'CompanyNumber' column and use a navigator to page through. In other words, I'd like the DataGridView to show me all the lines related to one company, then click the "next" arrow to show the next company, etc.
(I know I could do this with Xceed DataGrid, but I'm using Windows Forms not WPF, and I'd really prefer to do this with "pure" ADO.NET for this project.)
Update 2009-09-28:
So I have created a ComboBox filled from the same BindingSource, and configured its SelectedIndexChanged to change the Filter value on the DataGridView.
But still, filling the ComboBox--which should be easy!--continues to be a problem. I can either:
(a) fill it from the BindingSource, in which case I see multiples of each 'CompanyNumber' and I can't figure out a way to show only distinct values, or
(b) create another TableAdapter in the data source which is just a "Select DISTINCT CompanyNumber..." query, which mostly works, except that that first value of the list changes when I change the selection (e.g. if the ComboBox shows "100, 101, 102, 103" and I pick "102", then the list will show as "102, 101, 102, 103").
Any recommendations?
(Also, bonus if you can suggest how to make the BindingNavigator's arrows page through the 'CompanyNumber' filters instead of the items in the DataGridView... which is what I'd really like to see.)
What you could do is just force the DataGridView to sort CompanyName, this way all rows with the same company name are next to each other and the user can navigate the data grids with the paging that comes with it.
Alternatly, you could follow through with your combobox/DropDownList idea, which would be best. From what I understand when you select an item in the combobox everything in it changes?
Another way is to create two separate buttons, "Previous" "Next", that when clicked, will change the DataGridView's binding source to only show a certain company. You would need to store an array of company names, then store what the current DataGridView's binding source is displaying.
I ended up figuring it out myself, and the solution is clean and simple. Here are the basic steps:
create a DataView off of the table out of the DataSet
use the DataView.ToTable() method to create a new table filtered to only distinct values from the needed column ('CompanyNumber')
create a BindingSource which uses the new DataTable as its DataSource
bind the ComboBox to the new BindingSource
bind the BindingNavigator to the new BindingSource
Because the ComboBox and the BindingNavigator use the same BindingSource, they will update each other with the changes automagically.
Here's the rough code:
Private Sub CoNumsComboxBox_LoadData()
Dim dvCoNums As DataView, dtCoNums As DataTable
dvCoNums = New DataView(Me.ODBCDataSet.Tables("CompanyFundProfile"))
dvCoNums.Sort = "CompanyNumber ASC, FundNumber ASC"
dtCoNums = dvCoNums.ToTable("CompanyFundProfile", True, "CompanyNumber")
CoNums_BindingSource.DataSource = dtCoNums
CoNumsComboBox.DataSource = CoNums_BindingSource
CoNumsComboBox.DisplayMember = "CompanyNumber"
CoNumsComboBox.ValueMember = "CompanyNumber"
'attach handler which changes DataGridView1's filter when this changes
AddHandler ToolStripComboBox1.SelectedIndexChanged, AddressOf CoNumsComboBox_SelectedIndexChanged
CompanyFundProfile_BindingNavigator.BindingSource = CoNums_BindingSource
End Sub