数据表具有空值 [英] Data Table has null values

问题描述

在 FbuildingSettings.vb - 表单

Public camButtonDtable As DataTable

然后我用它在 Fbuilding.vb - Form

Then I used it in Fbuilding.vb - Form

Dim names = From row In FbuildingSettings.camButtonDtable.AsEnumerable() Select row.Field(Of String)("Building") Distinct
    For Each word In names
        ComboBox1.Items.Add(word)
    Next

几乎可以做我想要的，从列中获取每个不同的数据。所以我在 FbuildingSettings.vb中使用该代码

Pretty much do what I want, get each of the distinct data from a column. So I used that code in FbuildingSettings.vb

Dim names = From row In camButtonDtable.AsEnumerable() Select row.Field(Of String)("Building") Distinct
    For Each word In names
        comboBuilding.Items.Add(word)
    Next

我收到错误：



尝试这个：公共camButtonDtable作为新的DataTable - 它编译，但是comboBox不显示一个东西。

我做错了什么？

I get the error:

Tried this : Public camButtonDtable As New DataTable - it did compiled, but the comboBox does not display a thing.
What am I doing wrong?

推荐答案

解决方案（这是我使用的）：

FbuildingSettings.camButtonDtable = databaseFunctions.GetDataTable(queryBtn) 'to iniatialize data on cambtndtable

这应该是这样的东西（不确定） ）：

This should be something like this (not really sure):

Dim queryBtn As String = "SELECT * FROM tblCameraButtons"
FbuildingSettings.camButtonDtable = <DataTable>.Fill(queryBtn)

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