Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
203 views
in Technique[技术] by (71.8m points)

.net - Check if Column is empty

I am looking on how to check the column data of a specific row. I found this:

For Each row In tablePiglet.Rows ' - data table
        If Not DBNull.Value.Equals(row("CurrentLocation")) Then
            MessageBox.Show("Not Empty")
        Else
            MessageBox.Show("Empty")
        End If
    Next

I tried to run the app, and the code does not execute. I added a breakpoint in For Each but it just ended. Why is that? There had been yet a data on CurrentLocation field, so it should display empty.

What I want is to check whether that row's CurrentLocation is empty or not.
Something like : SELECT CurrentLocation FROM tableFoo WHERE id=1 then check if its empty or not.
Is the code above the right thing to do? Or are there other better ways?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

try this:

    For Each _dtrow as DataRow In tablePiglet.Rows ' - data table
        If _dtrow.Item("CurrentLocation").toString IsNot Nothing Or
           _dtrow.Item("CurrentLocation").toString <> vbNullString Then

              MessageBox.Show("Not Empty")
        Else
              MessageBox.Show("Empty")

        End If
    Next

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...