VB.NET 2010数据库搜索

Question

I have a ms access database connected to my vb application through the data wizard. i want to allow the user to search the database and display their results on a datagrid. for example user searches for 50 – 55 year Old man under 1.8 meters in height

so far i can display the total amount of people on the database with this code

    Private Sub lblTotalPeople_Click(sender As System.Object, e As System.EventArgs) Handles lblTotalPeople.Click
    Dim con As OleDbConnection = New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\AssignmentDatabase.accdb")
    ' Use wildcard'
    Dim cmd As OleDbCommand = New OleDbCommand("Select COUNT(*) From Table1", con)
    '' or Where username='" & TextBox1.Text & "'
    con.Open()
    Dim myDA As OleDbDataAdapter = New OleDbDataAdapter(cmd)
    Dim myDataSet As DataSet = New DataSet()
    myDA.Fill(myDataSet, "Table1")
    DataGridView2.DataSource = myDataSet.Tables("Table1").DefaultView

End Sub

how would i search the database based on what the user searches or what would i use?

Answer 1

Assuming you don't already you need to learn how to use SQL.

In your code above the SQL statement is

Select COUNT(*) From Table1

You would need to replace this SQL with a search that uses a value from the user (most likely from a textbox). This text

'' or Where username='" & TextBox1.Text & "'

appears to be part way to some SQL that may work but it looks dangerous. You should also research SQL Injection as using this directly means users could access/damage your Access database.