使用VB.net和Excel（组合框和搜索）

Question

New to programming and need to make a program in VB to interact with the Excel in the background

The Idea is to have two combo boxes, one "country", the other "city" (If country chosen, list of cities would be reduced to that country; if city is chosen, country would be selected automatically);

I have a DataGridView which displays two columns from the excel speadsheet, the person's fist name and the last name.

So given the city or a country/city a list of people would be displayed living in that country.

Also I'm trying to make a searchbox, whereby when you type into a textfield, given what you have typed so far it would filter the first name (containing what you have typed) in the GridView.

So far I have managed to get other things working, such as radiobuttons and checkboxes with different options.

I could not find anything that would work in regards to the comboboxes and the search field (without a button, so "live" filtering process would need to take place).

I am comfortable with SQL so I've been using sql so far to send queries to the excel and retrieve info for the grid view.

Could you please help? (may be provide with the template of how I should code it....)

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I am using Visual Basic 2012 and OleDB 4.0 (If i'm not mistaken) to make the connection.

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Given the comments below, the workaround that I've found for the search-bar is to create a button, then make it as small as possible and hide it behind the search bar by 'sending it to the back' as making it invisible seemed to have disabled it completely...

Then I have used the below code for the button:

    Private Sub BtSearch_Click(sender As Object, e As EventArgs) Handles BtSearch.Click

    Try
        FillSearchResults("SELECT First_Name, Last_Name FROM [Database$] WHERE Country LIKE '%" & Country.Text & "%'")
        Country.Text = dt.Rows(0).Item(1)

    Catch ex As Exception
        MsgBox("Not Found")
    End Try

End Sub

And for the text Field (to make the search results come up when the user hits Enter):

Private Sub CountrySearch_TextChanged(sender As Object, e As EventArgs) Handles CountrySearch.TextChanged

    Me.AcceptButton = BtSearch

End Sub

Next step: I will probably try to apply the filter so that the user wouldn't have to hit enter for the grid view to update

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Any development I will post here, so that as suggested, if anyone else has the same problem, it would be clearer to see follow...

Answer 1

You can apply Filter to the BindingSource for a DataGridView . You can put that code in the event handler for a ComboBox 's SelectedIndexChanged event:

Private Sub myComboBox_SelectedIndexChanged(sender As Object, e As EventArgs) Handles myComboBox.SelectedIndexChanged
    bindingSourceForMyDataGridView.Filter = 
        "SomeColumn LIKE '%" & myComboBox.SelectedValue & "%'"
End Sub

There are other handlers for ComboBox that might be more applicable, like SelectedValueChanged or TextChanged .
There are also other values that may be more applicable, depending how the ComboBox is being populated, such as .Text or .SelectedText .

Answer 2

Okay Basically I've done the search as described in the question.

Regarding the combo boxes I've left one combo box.

Populated it through the GUI/Designer Mode:

• Select the combo box

• Click on the small arrow

• Click on Edit Items

• A window will pop-up - enter your options there (one option per line)

• Once you've done that, save it

Double click on it and code-mode should come up

I had a FillSearchResults Function which would send the SQL Statements to the excel and put that info into the grid view:

        Private Sub FillSearchResults(ByVal Query As String)

    Dim da As OleDbDataAdapter
    Dim dt As New DataTable

    'The Connection should already be open'

    da = New OleDbDataAdapter(Query, cn)
    dt.Clear()
    da.Fill(dt)

    'To name the columns and make it so that when the window size is changed the column widths would automatically adjust'
    With SearchResults
        .DataSource = dt
        .Columns(0).HeaderText = "First Name"
        .Columns(1).HeaderText = "Second Name"
        .Columns(2).HeaderText = "Country"
        .Columns(3).HeaderText = "Completed Fully"
        .Columns(0).Width = 70
    End With

    'To Color the whole rows depending if all of the information is complete (I do realise this is not the best way to do it but still...)'
    For i As Integer = 0 To Me.SearchResults.Rows.Count - 1
        If Me.SearchResults.Rows(i).Cells("Completed_Fully").Value.ToString = "No" Then
            Me.SearchResults.Rows(i).Cells("First_Name").Style.BackColor = Color.Cornsilk
            Me.SearchResults.Rows(i).Cells("Second_Name").Style.BackColor = Color.Cornsilk
            Me.SearchResults.Rows(i).Cells("Country").Style.BackColor = Color.Cornsilk
            Me.SearchResults.Rows(i).Cells("Completed_Fully").Style.BackColor = Color.Cornsilk

        ElseIf Me.SearchResults.Rows(i).Cells("Completed_Fully").Value.ToString = "Yes" Then
            Me.SearchResults.Rows(i).Cells("First_Name").Style.BackColor = Color.Azure
            Me.SearchResults.Rows(i).Cells("Second_Name").Style.BackColor = Color.Azure
            Me.SearchResults.Rows(i).Cells("Country").Style.BackColor = Color.Azure
            Me.SearchResults.Rows(i).Cells("Completed_Fully").Style.BackColor = Color.Azure

        Else
            Me.SearchResults.RowsDefaultCellStyle.BackColor = Color.Red
            Me.SearchResults.ClearSelection()
        End If
    Next

   'To Clear the first row/cell being selected'
    Me.SearchResults.ClearSelection()

End Sub

Now to link the country fields:

    Private Sub Country_SelectedIndexChanged(sender As Object, e As EventArgs) Handles Country.SelectedIndexChanged

    FillSearchResults(SELECT Country FROM Database WHERE Country LIKE '%" & Country.Text & "%' ")

End Sub

And Done :)

Whenever a country is selected, only results for that country would show

PS: I called the country combo box as "Country"...