如何验证DataGridViewCheckBoxCell是否被检查 [英] How to verify if a DataGridViewCheckBoxCell is Checked

问题描述

我已经将一个数据表绑定到一个 DataGridView ，这个数据表有一个名为Status的列，类型为$ code> Boolean 。我可以通过代码将值设置为 true 或 false 。

I have bound a data table to a DataGridView, this data table has a column called "Status" which is of type Boolean. I can set the value to true or false just fine via code.

但是，我无法弄清楚如何检查给定行是否已经被检查。这是我试图使用和编译的代码，显示错误指定的转换无效。

However, I can't figure out how to check to see if the given row is already checked or not. This is the code I am trying to use and compiling it shows the error "the specified cast is invalid".

任何帮助将不胜感激。

if (rowIndex >= 0)
{
    var cbxCell = (DataGridViewCheckBoxCell)dgvScan.Rows[rowIndex].Cells["Status"];

    if ((bool)cbxCell.Value)
    {
        // Do stuff
    }
    else
    {
        // Do other stuff
    }
}

推荐答案

问题是DataGridCheckBoxColumn的默认FALSE值为null，默认TRUE值为布尔值True。这会导致一个问题，因为布尔值不可为空。您可以通过两种方式解决这个问题：

The problem is that the default FALSE value for a DataGridCheckBoxColumn is null, and the Default TRUE value is the boolean value True. This causes a problem because boolean values are not nullable. You can solve this problem two ways:

    if (cbxCell.Value != null && (bool)cbxCell.Value)
    {
        do stuff;
    }

另一种解决方法是将列的TrueValue属性设置为某些值。这可以在设计时完成，如图所示：

The other way to solve this is set the TrueValue property of the column to some value. This can be done at design time as shown:

然后你可以写：

    if ((string)cbxCell.Value == "T")
    {
        do stuff;
    }

这是因为字符串可以空。

This works because Strings are nullable.

请注意：即使我将FalseValue设置为F，假值仍然为null，因此我建议忽略FalseValue属性。

Please note: Even though I set the FalseValue to be F the false value still seems to be null, so I suggest ignoring the FalseValue property.

另外一个注意事项：如果你像上面那样把一些东西放在TrueValue中，然后尝试擦除它，True值将变为null（ouch），需要你删除列，然后重新添加它，以便将它恢复到默认条件。或者您可以按照以下代码更改代码：

One other note: IF you put something in TrueValue as above and then attemp to erase it, True value becomes null (ouch), requireing you to delete the column and then re-add it in order to restore it to the default condition. Or you can change it in code as follows:

((DataGridViewCheckBoxColumn)DataGridView1.Columns["Selected"]).TrueValue = true

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