如何检查是否在 DataGridView 上选择了任何行？答案

【问题标题】：How to check if have any row selected on DataGridView?如何检查是否在 DataGridView 上选择了任何行？
【发布时间】：2016-02-28 05:21:15
【问题描述】：

我正在尝试检查是否在 DataGridView 上选择了任何行。问题是当我尝试执行下面的行时。我该如何解决这个问题？

试试这个

 private void btnExcluir_Click(object sender, EventArgs e) {
            int row = gridUsuarios.CurrentRow.Index;
            Console.WriteLine(row);
 }

例外

System.Transactions Critical: 0 : <TraceRecord xmlns="http://schemas.microsoft.com/2004/10/E2ETraceEvent/TraceRecord" Severity="Critical"><TraceIdentifier>http://msdn.microsoft.com/TraceCodes/System/ActivityTracing/2004/07/Reliability/Exception/Unhandled</TraceIdentifier><Description>Unhandled exception</Description><AppDomain>ControleUsuarios.vshost.exe</AppDomain><Exception><ExceptionType>System.NullReferenceException, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</ExceptionType><Message>Object reference not set to an instance of an object.</Message><StackTrace>   at ControleUsuarios.Form1.btnExcluir_Click(Object sender, EventArgs e) in c:\Users\fernando\Documents\Visual Studio 2012\Projects\ControleUsuarios\ControleUsuarios\Form1.cs:line 44
   at System.Windows.Forms.Control.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
   at System.Windows.Forms.Control.WmMouseUp(Message&amp;amp; m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message&amp;amp; m)
   at System.Windows.Forms.ButtonBase.WndProc(Message&amp;amp; m)
   at System.Windows.Forms.Button.WndProc(Message&amp;amp; m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message&amp;amp; m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message&amp;amp; m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG&amp;amp; msg)
   at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.Run(Form mainForm)
   at ControleUsuarios.Program.Main() in c:\Users\fernando\Documents\Visual Studio 2012\Projects\ControleUsuarios\ControleUsuarios\Program.cs:line 16
   at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
   at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
   at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
   at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()</StackTrace><ExceptionString>System.NullReferenceException: Object reference not set to an instance of an object.
   at ControleUsuarios.Form1.btnExcluir_Click(Object sender, EventArgs e) in c:\Users\fernando\Documents\Visual Studio 2012\Projects\ControleUsuarios\ControleUsuarios\Form1.cs:line 44
   at System.Windows.Forms.Control.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
   at System.Windows.Forms.Control.WmMouseUp(Message&amp;amp; m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message&amp;amp; m)
   at System.Windows.Forms.ButtonBase.WndProc(Message&amp;amp; m)
   at System.Windows.Forms.Button.WndProc(Message&amp;amp; m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message&amp;amp; m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message&amp;amp; m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG&amp;amp; msg)
   at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.Run(Form mainForm)
   at ControleUsuarios.Program.Main() in c:\Users\fernando\Documents\Visual Studio 2012\Projects\ControleUsuarios\ControleUsuarios\Program.cs:line 16
   at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
   at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
   at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
   at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()</ExceptionString></Exception></TraceRecord>
The program '[4584] ControleUsuarios.vshost.exe: Program Trace' has exited with code 0 (0x0).
The program '[4584] ControleUsuarios.vshost.exe: Managed (v4.0.30319)' has exited with code -1 (0xffffffff).

【问题讨论】：

您没有选择任何行，因此 CurrentRow 属性为空。添加一个空检查。

标签： c# datagridview

【解决方案1】：

您可以使用SelectedRows 属性进行验证。

if( gridUsuarios.SelectedRows != null && gridUsuarios.SelectedRows.Count > 0 )
{
    // logic.
}

【讨论】：

【解决方案2】：

@HariPrasad 的答案是正确的，但效率低下。它使用Count，即使您只想知道是否至少选择了一个并且行变得不共享（see）。如果您将DataGridView 子类化（并且我建议您在项目中使用的每个组件都使用该子类），您可以创建此属性：

[Browsable(false)]
public bool SelectedOneOrMore
{
    get
    {
        return Rows.GetFirstRow(DataGridViewElementStates.Selected) != -1;
    }
}

【讨论】：