通过螺纹滚动时更新的DataGridView [英] Updating DataGridView via a thread when scrolling

问题描述

我坚持我的这个问题，如果有人给我

$ B $解决了这个

问题将是很大的帮助b

我所试图做的是：

1）Intialize在窗体加载事件一个DataTable数据表和它的默认视图分配给

datagridview的dgvresult

2）在点击一个按钮启动一个STA线程（其实我跟华廷IE因此

工作

需要使线程STA）这就要求它创建一个相同的数据表的方法。

DT为DataTable的步骤1中创建和。然后将300行此数据表

3）调用它合并了这个DT与数据表中，因此在这里嘛更新dgvresult
委托是我的问题：

下面是我刚才所描述的步骤的代码片段：

 静态类节目
 {
 ///<总结> 
 ///的主要入口点application.This方法制成STAThread因为我需要并初始化华廷IE在frmMain 
 ///<的形式负荷; /总结> 
 [STAThread] 
静态无效的主要（）
 {
 Application.EnableVisualStyles（）; 
 Application.SetCompatibleTextRenderingDefault（假）; 
 Application.Run（新frmMain（））; 
} 
} 
  

/// frmmain代码

  ///<总结> 
 ///代表结合最新的数据表到gridview的
 ///< /总结> 
 ///< PARAM NAME =DT>该数据表与主数据表<合并; /参数> 
 
委托无效Bind_DataTable_to_GridView_Delegate（DataTable的DT）; 
 
私人无效bind_DataTable_to_GridView（DataTable的DT）
 {
 
如果（dgvResult.InvokeRequired）
 {
 Bind_DataTable_to_GridView_Delegate德尔=新Bind_DataTable_to_GridView_Delegate（bind_DataTable_to_GridView ）; 
 dgvResult.Invoke（德尔，新的对象[] {DT}）; 
} 
，否则
 {
 
 
 
 datatable.Merge（DT）; 
 
 
 dgvResult.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells; //自动调整大小在GridView 
 
 
 
的foreach（在dgvResult.Columns的DataGridViewColumn dgvcol）
 {
 dgvcol.SortMode = DataGridViewColumnSortMode.NotSortable; 
} 
 
 
} 
 
 
} 
 
 WatiN.Core.IE即; 
 
私人无效frmMain_Load（对象发件人，EventArgs五）
 {
 
 // intialize华廷IE 
即=新的IE（URLs.mainURL）; 
 
 // DataTable中
的DataColumn datacolumn1列初始化=新的DataColumn（字）; 
 
 //添加DataTable中$ B $列b datatable.Columns.Add（datacolumn1）的; 
 
 
 //使DataTable中永久
 datatable.AcceptChanges（）; 
 
 //分配的datatble默认视图dgvResult的DataSource 
 dgvResult.DataSource = datatable.DefaultView; 
 
的foreach（在dgvResult.Columns的DataGridViewColumn dgvcol）
 {
 dgvcol.SortMode = DataGridViewColumnSortMode.NotSortable; 
} 
} 
 
私人无效btnGenerateWords_Click（对象发件人，EventArgs五）
 {
试
 {
 
如果（datatable.Rows.Count大于0）
 {
 //初始化GenerateWords线程
 GenerateWords =新主题（GenW）; 
 
 //设置单元状态为静态
 GenerateWords.SetApartmentState（ApartmentState.STA）; 
 
 //启动线程GenerateWords 
 GenerateWords.Start（）; 
} 
 
} 
 #endregion 
 
 
 
＃地区的GenerateWords线程
 ///<功能;总结>的GenerateWords螺纹
 ///< 
 ///功能; /总结> 
 
无效GenW（）
 {
 
的DataColumn datacolumn1 =新的DataColumn（字）; 
 
 //添加DataTable中
 DataTable的DT =新的DataTable（）列; 
 dt.Columns.Add（datacolumn1）; 
 
 //此时表具有说20行
为（INT dtindex = 0; dtindex< datatable.Rows.Count; dtindex ++）
 {
 / *添加了成功300新鲜行代码dt的* / 
 
 //发送dgvresult的数据源作为DT 
 bind_DataTable_to_GridView（DT）; 
 dt.Clear（）; 
} 
} 
} 
  

现在问题出现了，当我在datagridview的许多行（让我们假设1000）

现在，如果在UI我不跟datagridview的事情该代码工作正常没有错误。

但是，如果我保持滚动datgridview当绑定方法被调用的应用程序提供了错误，只是终止，由于其未能及时更新我猜想datgridview（或者因故障在调用的datagridview）

下面是错误： -
当我运行exe我得到这个： -

未处理的异常已发生在你的应用程序。

对象引用未设置为一个对象。

  System.NullReferenceException：对象不设置到对象的实例。在System.Windows.Forms.DataGridViewTextBoxCell.PaintPrivate（图形图像，矩形clipBounds，矩形cellBounds，的Int32的rowIndex，DataGridViewElementStates cellState 
，对象FormattedValue的，字符串ERRORTEXT，的DataGridViewCellStyle cellStyle，DataGridViewAdvancedBorderStyle advancedBorderStyle，DataGridViewPaintParts paintParts，布尔computeContentBounds，布尔computeErrorIconBounds布尔油漆）
在System.Windows.Forms.DataGridViewTextBoxCell.Paint（图形图像，矩形clipBounds，矩形cellBounds，的Int32的rowIndex，DataGridViewElementStates cellState，对象的值，对象FormattedValue的，字符串ERRORTEXT，的DataGridViewCellStyle cellStyle，DataGridViewAdvancedBorderStyle advancedBorderStyle，DataGridViewPaintParts paintParts）
在System.Windows.Forms.DataGridViewCell.PaintWork（图形图像，矩形clipBounds，矩形cellBounds，的Int32的rowIndex，DataGridViewElementStates cellState，的DataGridViewCellStyle cellStyle，DataGridViewAdvancedBorderStyle advancedBorderStyle，DataGridViewPaintParts paintParts）
在System.Windows。 Forms.DataGridViewRow.PaintCells（图形图像，矩形clipBounds，矩形rowBounds，的Int32的rowIndex，DataGridViewElementStates的RowState，布尔isFirstDisplayedRow，布尔isLastVisibleRow，DataGridViewPaintParts paintParts）
在System.Windows.Forms.DataGridViewRow.Paint（图形显卡，矩形clipBounds ，矩形rowBounds，的Int32的rowIndex，DataGridViewElementStates的RowState，布尔isFirstDisplayedRow，布尔isLastVisibleRow）
在System.Windows.Forms.DataGridView.PaintRows（图形克，矩形boundingRect，矩形clipRect，布尔singleHorizo​​ntalBorderAdded）
的系统。 Windows.Forms.DataGridView.PaintGrid（图形克，矩形gridBounds，矩形clipRect，布尔singleVerticalBorderAdded，布尔singleHorizo​​ntalBorderAdded）在System.Windows.Forms.DataGridView.OnPaint（PaintEventArgs的E）
。在System.Windows.Forms.Control的。 PaintWithErrorHandling（PaintEventArgs的E，Int16的层，布尔disposeEventArgs）在System.Windows.Forms.Control.WmPaint（消息和;米）
在System.Windows.Forms.Control.WndProc（消息和M）
在System.Windows.Forms.DataGridView.WndProc（消息和M）
在System.Windows.Forms的.Control.ControlNativeWindow.OnMessage（消息和M）
在System.Windows.Forms.Control.ControlNativeWindow.WndProc（消息和M）
在System.Windows.Forms.NativeWindow.Callback（IntPtr的的HWND， INT32味精，IntPtr的WPARAM，IntPtr的LPARAM）
  

我检查过了VS，它给出了这个错误Program.cs的在这条线： - Application.Run（新frmMain（））;

如何解决这个问题？

任何帮助将不胜感激。
谢谢您：）

解决方案

你应该尝试

  this.Invoke（德尔，新的对象[] {DT}）; //应该工作
  

而不是

  dgvResult.Invoke（德尔，新的对象[] {DT}）; //错误
  

在bind_DataTable_to_GridView（）

I am stuck with this problem of mine and it will be great help if someone solves this

problem for me

What I am trying to do is :

1) Intialize a DataTable datatable in form load event and assign its defaultview to a

datagridview dgvresult

2) On click of a button start an STA thread (I am actually working with WatIN IE hence the

need for making the thread STA ) which calls a method which creates an identical DataTable

dt as datatable created in step 1 and then adds 300 rows to this datatable.

3) calls a delegate which merges this dt with datatable and thus updates the dgvresult Well here is my problem :

Here is the code Snippet for the steps I just described :

static class Program
{
    /// <summary>
    /// The main entry point for the application.This method is made STAThread as I need to intialize WatIN IE in the form load of frmMain
    /// </summary>
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new frmMain());
    }
}

///frmmain code

 /// <summary>
    /// Delegate which Binds updated Datatable to gridview 
    /// </summary>
    /// <param name="dt">The Datatable to be merged with main datatable</param>

    delegate void Bind_DataTable_to_GridView_Delegate(DataTable dt);

    private void bind_DataTable_to_GridView(DataTable dt)
    {

            if (dgvResult.InvokeRequired)
            {
                Bind_DataTable_to_GridView_Delegate del = new Bind_DataTable_to_GridView_Delegate(bind_DataTable_to_GridView);
                dgvResult.Invoke(del, new object[] { dt });
            }
            else
            {



                    datatable.Merge(dt);


                    dgvResult.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells;               //Autosizes the gridview 



                    foreach (DataGridViewColumn dgvcol in dgvResult.Columns)
                    {
                        dgvcol.SortMode = DataGridViewColumnSortMode.NotSortable;
                    }


            }


    }

     WatiN.Core.IE ie;     

    private void frmMain_Load(object sender, EventArgs e)
    {

        //intialize WatIN IE
         ie = new IE(URLs.mainURL);

        //initialization of columns in datatable
        DataColumn datacolumn1 = new DataColumn("Words");

        //Adding of columns in datatable
        datatable.Columns.Add(datacolumn1);


        //Making the datatable permanent
        datatable.AcceptChanges();

        //Assigning default view of datatble as dgvResult's datasource
        dgvResult.DataSource = datatable.DefaultView;

        foreach (DataGridViewColumn  dgvcol in dgvResult.Columns)
        {
            dgvcol.SortMode = DataGridViewColumnSortMode.NotSortable;
        }
    }

    private void btnGenerateWords_Click(object sender, EventArgs e)
    {
        try
        {

            if (datatable.Rows.Count > 0)
            {
                //Initializes the GenerateWords Thread           
                GenerateWords = new Thread(GenW);

                //Sets the apartment state to Static
                GenerateWords.SetApartmentState(ApartmentState.STA);

                //Starts the GenerateWords Thread           
                GenerateWords.Start();
            }

    }
    #endregion



    #region function of GenerateWords thread
    /// <summary>
    /// function of GenerateWords thread
    /// </summary>

    void GenW()
    {

                DataColumn datacolumn1 = new DataColumn("Words");

                //Adding of columns in datatable
                DataTable dt = new DataTable();
                dt.Columns.Add(datacolumn1);

            //At this point datatable has say 20 rows
            for (int dtindex = 0; dtindex < datatable.Rows.Count; dtindex++)
            {
                /*Code Which adds successfully 300 fresh rows to dt*/

                //sends datasource of dgvresult as dt
                bind_DataTable_to_GridView(dt);
                dt.Clear();
            }
        }
    }

Now the problem arises when I have many rows in datagridview(lets assume 1000)

Now if in UI I dont do anything with datagridview this code works fine without errors

But if I keep scrolling the datgridview when the bind method is called the application gives error and just terminates due to its failure to update the datgridview I suppose ( or maybe due to failure in invoking the datagridview )

Here is the error :-- When I run the exe I get this :-

Unhandled exception has occured in your application.

Object reference not set to an object.

System.NullReferenceException: Object reference not set to an instance of an object.
  at System.Windows.Forms.DataGridViewTextBoxCell.PaintPrivate(Graphics graphics, Rectangle clipBounds, Rectangle cellBounds, Int32 rowIndex, DataGridViewElementStates cellState, Object formattedValue, String errorText, DataGridViewCellStyle cellStyle, DataGridViewAdvancedBorderStyle advancedBorderStyle, DataGridViewPaintParts paintParts, Boolean computeContentBounds, Boolean computeErrorIconBounds, Boolean paint)
  at System.Windows.Forms.DataGridViewTextBoxCell.Paint(Graphics graphics, Rectangle clipBounds, Rectangle cellBounds, Int32 rowIndex, DataGridViewElementStates cellState, Object value, Object formattedValue, String errorText, DataGridViewCellStyle cellStyle, DataGridViewAdvancedBorderStyle advancedBorderStyle, DataGridViewPaintParts paintParts)
  at System.Windows.Forms.DataGridViewCell.PaintWork(Graphics graphics, Rectangle clipBounds, Rectangle cellBounds, Int32 rowIndex, DataGridViewElementStates cellState, DataGridViewCellStyle cellStyle, DataGridViewAdvancedBorderStyle advancedBorderStyle, DataGridViewPaintParts paintParts)
  at System.Windows.Forms.DataGridViewRow.PaintCells(Graphics graphics, Rectangle clipBounds, Rectangle rowBounds, Int32 rowIndex, DataGridViewElementStates rowState, Boolean isFirstDisplayedRow, Boolean isLastVisibleRow, DataGridViewPaintParts paintParts)
  at System.Windows.Forms.DataGridViewRow.Paint(Graphics graphics, Rectangle clipBounds, Rectangle rowBounds, Int32 rowIndex, DataGridViewElementStates rowState, Boolean isFirstDisplayedRow, Boolean isLastVisibleRow)
  at System.Windows.Forms.DataGridView.PaintRows(Graphics g, Rectangle boundingRect, Rectangle clipRect, Boolean singleHorizontalBorderAdded)
  at System.Windows.Forms.DataGridView.PaintGrid(Graphics g, Rectangle gridBounds, Rectangle clipRect, Boolean singleVerticalBorderAdded, Boolean singleHorizontalBorderAdded) at System.Windows.Forms.DataGridView.OnPaint(PaintEventArgs e)
  at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer, Boolean disposeEventArgs) at System.Windows.Forms.Control.WmPaint(Message& m)
  at System.Windows.Forms.Control.WndProc(Message& m)
  at System.Windows.Forms.DataGridView.WndProc(Message& m)
  at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
  at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
  at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

I checked it through the VS , It gives this error in Program.cs in this line :- Application.Run(new frmMain());

How to get around this problem?

Any help will be appreciated. Thank You :)

解决方案

you should try

this.Invoke(del, new object[] { dt }); //Should Work

instead of

dgvResult.Invoke(del, new object[] { dt }); //Error

in bind_DataTable_to_GridView()

这篇关于通过螺纹滚动时更新的DataGridView的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！