vb.net da.fill(dt) 上的值不能为空
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value cannot be null on da.fill(dt)
提问by ivandinglasan
sqlconn.Open()
Dim da As New SqlDataAdapter("select * from tblOfficeEquipmentCategory", sqlconn)
Dim dt As DataTable
da.Fill(dt)
cmbCategory.DataSource = dt
cmbCategory.DisplayMember = "CAT_ID"
cmbCategory.ValueMember = "CAT_NAME"
sqlconn.Close()
returning an error pointing to da.fill(dt)
返回指向 da.fill(dt) 的错误
Run-time exception thrown : System.ArgumentNullException - Value cannot be null.
抛出的运行时异常：System.ArgumentNullException - 值不能为空。
回答by csharp
you should assign your DataTablewith newkeyword :
你应该分配你DataTable的new关键字：
Dim dt As New DataTable()
回答by Kasnady
Dim da As New SqlDataAdapter("select * from tblOfficeEquipmentCategory", sqlconn)
Dim dt As NEW DataTable
da.Fill(dt)
Without NEW, your data don't have place to store cause you just get variable but don't get the form.
如果没有 NEW，您的数据就没有地方存储，因为您只会获得变量但无法获得表格。
Update
更新
Beside that, i just have found that your data won't show up and will got error about execute.
除此之外，我刚刚发现您的数据不会显示，并且会出现关于执行的错误。
Like oledbcommand.executenonquery()before sqlconn.close, but i didn't see your command code.
像oledbcommand.executenonquery()以前一样sqlconn.close，但我没有看到您的命令代码。
sqlconn.Open()
Dim da As New SqlDataAdapter("select * from tblOfficeEquipmentCategory", sqlconn)
Dim dt As DataTable
da.Fill(dt)
cmbCategory.DataSource = dt
cmbCategory.DisplayMember = "CAT_ID"
cmbCategory.ValueMember = "CAT_NAME"
oledbcommand.executenonquery()<<<< HERE
sqlconn.Close()
回答by ivandinglasan
sqlconn.Open()
Dim da As New SqlDataAdapter("select * from tblOfficeEquipmentCategory", sqlconn)
Dim dt As New DataTable
da.Fill(dt)
cmbCategory.DataSource = dt
cmbCategory.DisplayMember = "CAT_NAME"
cmbCategory.ValueMember = "CAT_ID"
sqlconn.Close()
its working now thanks for the answers, i just re assigned the displaymember and valuemember
它现在正在工作，感谢您的回答，我刚刚重新分配了 displaymember 和 valuemember
its not returning cannot bind to value member error
它不返回无法绑定到值成员错误
