string.IsNullOrWhiteSpace() 和 string.IsNullOrEmpty() 中的 NullReferenceException [英] NullReferenceException in string.IsNullOrWhiteSpace() and string.IsNullOrEmpty()

问题描述

我正在检查可能为空/空/空的列的单元格值，所以我需要一些东西来避免 NullReferenceException.

I'm checking the cell values of cells of a column that might or not be empty/null so I needed something to avoid a NullReferenceException.

我该怎么做，因为即使使用 IsNullOrWhiteSpace() 和 IsNullOrEmpty() 我也会以某种方式得到该异常.

How do I do that since even with the IsNullOrWhiteSpace() and IsNullOrEmpty() I get that exception somehow.

这是我正在使用的代码的一部分:

Here's part of the code I'm using:

s = "Total = " + dataGridView1.Rows[0].Cells.Count +
    "0 = " + dataGridView1.Rows[0].Cells[0].Value.ToString() +
    "/n  1 = " + dataGridView1.Rows[0].Cells[1].Value.ToString() +
    "/n  2= " + dataGridView1.Rows[0].Cells[2].Value.ToString() +
    "/n  3 = " + dataGridView1.Rows[0].Cells[3].Value.ToString() +
    "/n  4= " + dataGridView1.Rows[0].Cells[4].Value.ToString() +
    "/n  5 = " + dataGridView1.Rows[0].Cells[5].Value.ToString() +
    "/n  6= " + dataGridView1.Rows[0].Cells[6].Value.ToString() +
    "/n  7 = " + dataGridView1.Rows[0].Cells[7].Value.ToString();

    if (string.IsNullOrEmpty(dataGridView1.Rows[0].Cells[8].Value.ToString()))
    {

    }
    else
    {
        s += "/n  8 = " + dataGridView1.Rows[0].Cells[8].Value.ToString();
    }

我试过那些方法我试过把它==null，我试过!=null.还有什么或者我做错了什么，我该怎么做?

I've tried those methods I've tried putting it ==null, I've tried !=null. What else is there or what am I doing wrong exactly and how do I do it right?

推荐答案

您的代码可能会在很多地方抛出该异常..

the are a lot of places you code could throw that exception ..

dataGridView1.Rows[0]  //here
             .Cells[0] //here
             .Value    //and here
             .ToString() 

我相信您不需要 ToString() 只需输入:

I belive you don't need the ToString() just type:

"... "+ dataGridView1.Rows[0].Cells[0].Value

在您的 if 语句中执行以下操作:

in your ifstatement do this:

if (string.IsNullOrEmpty(dataGridView1.Rows[0].Cells[8].Value as string))

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