OLEDB-选择计数不起作用 [英] OLEDB - select Count not working

问题描述

在下面可以找到我到目前为止所做的事情，但不幸的是它没有用.

Find below what I've done so far, but unfortunately it's not working.

       Private BS as New BindingSource
       Dim ds As New DataSet
     ' Make the Connection
       Using con As New OleDb.OleDbConnection("PROVIDER=Microsoft.Jet.OLEDB.4.0;Data Source = Database1.mdb")
       con.Open()
       Dim Sql = "SELECT COUNT ([Eventname]) FROM Eventproposal"
       Dim da = New OleDb.OleDbDataAdapter(Sql, con)
       da.Fill(ds, "Eventproposal")
     ' Set the Binding Source
      bs.DataSource = ds.Tables("Eventproposal")
     con.Close()
 End Using
    TextBox1.DataBindings.Add("Text", bs, "")

推荐答案

再加上一些事情，您应该使用;

Couple things, you should end all SQL Commands to MS Access with ;

Dim Sql = "SELECT COUNT ([Eventname]) FROM Eventproposal;"

您没有命名您的列，当您尝试通过名称访问它时会给您一个错误.

And you did not name your column which will give you an error when you attempt to access it by name.

Dim Sql = "SELECT COUNT ([Eventname]) AS Eventname FROM Eventproposal;"

我相信它会给它起一个名字，但不会给您带来什么想法.最后，进行绑定时，必须引用表中字段的名称.

I believe it will give it a name but not what your thinking. Lastly, when you do your binding, you will have to reference the name of the field in the table.

TextBox1.DataBindings.Add("Text", bs, "Eventname")

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