Here comes the trouble.
I want to delete all rows from datagridview.
This how i add rows:

麻烦来了。我想从datagridview中删除所有行。下面是我添加行的方式：

private void ReadCompleteCallback(object clientHandle, Opc.Da.ItemValueResult[]     results)
{
    foreach (Opc.Da.ItemValueResult readResult in results)
    {
        dataGridView1.Invoke(new MethodInvoker(() => dataGridView1.Rows.Add(readResult.ItemName, readResult.Quality, readResult.Timestamp,readResult.Value)));        
    }
}                              

And its how i clear gridview:

这就是我清理网格视图的方式：

private void treeView1_SelectionsChanged(object sender, EventArgs e)
{
    dataGridView1.Rows.Clear();
    items = new Opc.Da.Item[treeView1.SelectedNodes.Count]; 
    foreach (TreeNode x in treeView1.SelectedNodes) {
        items[treeView1.SelectedNodes.IndexOf(x)] = new Opc.Da.Item();
        items[treeView1.SelectedNodes.IndexOf(x)].ItemName = x.Text; 
    }

    group.AddItems(items);
    group.Read(group.Items, 123, new Opc.Da.ReadCompleteEventHandler(ReadCompleteCallback), out req);
}

in debug i see that dataGridVIew1.Rows.Count=0, but on form, grid doesnt become clear. what a point?
on each selection in tree, i want to see new rows in table.

在调试中，我看到dataGridVIew1.Rows.Count=0，但在表单上，网格并不清晰。这是什么意思？在树中的每个选择上，我希望看到表中的新行。

优秀答案推荐

I'm betting you just need to refresh the datagrid. Try this:

我打赌你只需要刷新数据网格。试试这个：

dataGridView1.Rows.Clear();
dataGridView1.Refresh();

If this works... you might want to rethink this part of your application.

如果这行得通..。您可能需要重新考虑应用程序的这一部分。

If I remember correctly, I set the DataSource property to null to clear the DataGridView:

如果我没记错的话，我将DataSource属性设置为NULL以清除DataGridView：

datagridview.DataSource = null;

To clear the datagridview write the following code:

要清除datagridview，请编写以下代码：

dataGridView1.DataSource=null;

Basically below code line is only useful in data binding scenarios

基本上，下面的代码行仅在数据绑定方案中有用

datagridview.DataSource = null; 

otherwise below is the used when no data binding and datagridview is populated manually

否则，在未手动填充任何数据绑定和datagridview时使用下面的

dataGridView1.Rows.Clear();
dataGridView1.Refresh();

So, check first what you are doing.

所以，首先要检查一下你在做什么。

If you want clear a dataGridView not binded to DataSource but manually loaded you can use this simple code:

如果希望清除未绑定到数据源但手动加载的dataGridView，可以使用以下简单代码：

datagridview.Rows.Clear();
datagridview.Columns.Clear();

all you need to do is clear your datatable before you fill it... and then just set it as you dgv's datasource

您所需要做的就是在填充数据表之前将其清除...然后将其设置为您DGV的数据源

I have this piece of code i hope it may help u.

我有这段代码，希望它能帮助你。

int numRows = dgbDatos.Rows.Count;    
for (int i = 0; i < numRows; i++)
{
    try
    {    
        int max = dgbDatos.Rows.Count - 1;
        dgbDatos.Rows.Remove(dgbDatos.Rows[max]);

    }
    catch (Exception exe)
    {
        MessageBox.Show("You can´t delete A row " + exe, "WTF",
        MessageBoxButtons.OK, MessageBoxIcon.Information);
    }
}

Simply if your are trying to rebind your Data Grid View just code this:

简单地说，如果你试图重新绑定你的数据网格视图，只需编写以下代码：

DataGridView1.DataSource = DataSet.Tables["TableName"];

OR

或

DataGridView.DataSource = DataTable;

else if you trying to to clear your Data Grid View just code this:

否则，如果您尝试清除数据网格视图，只需编写以下代码：

DataGridView.DataSource = null;
DataGridView.Rows.Clear();
DataGridView.Refresh();

and add any method or event to bind Data Grid View Again below this line of code....

并在该行代码下面添加任何方法或事件以再次绑定数据网格视图...

try setting RowCount to 0(allowuserstorows should be false), along with calling clear

尝试将RowCount设置为0(Allowuserstorrow应为False)，同时调用Clear

This is one way of doing it:

这是实现这一目标的一种方法：

datagridview.DataSource = null;
datagridview.Refresh();

I hope it works for you because it is working for me.

我希望它对你管用，因为它对我管用。

try:

尝试：

datagrid.DataSource = null;
datagrid.DataBind();

Basically you will need to clear the datasource your binding to the grid.

基本上，您需要清除绑定到网格的数据源。

Try this Method

试试这个方法

dataGridView1.DataSource = dt;
dt.Rows.Clear();

dataGridView1.DataSource=null;

Set the datasource property to an empty string then call the Clear method.

将数据源属性设置为空字符串，然后调用Clear方法。

I don't like messing with the DataSource personally so after discussing the issue with an IT friend I was able to discover this way which is simple and doesn't effect the DataSource. Hope this helps!

我不喜欢亲自摆弄数据源，所以在与一位IT朋友讨论了这个问题后，我发现了这种简单且不会影响数据源的方法。希望这个能帮上忙！

foreach (DataGridViewRow row in dataGridView1.Rows) 
{
    foreach (DataGridViewCell cell in row.Cells)
    {
        cell.Value = "";
    }
}

If your DataGridView does not have any DataSource the solution does not come by manipulating it.

如果DataGridView没有任何数据源，则解决方案不是通过操作它来实现的。

You will always have an empty row if you have the AllowUserToAddRows property set to true.

如果将AllowUserToAddRow属性设置为True，则始终有一个空行。

Put AllowUserToAddRows = false if you don't need permise this.

如果不需要许可，请设置AllowUserToAddRow=False。

I know it sounds crazy, but I solved this issue by
changing the datagrid.visible property to false and then to true.
It causes a very small blink, but it works for me (at least for now).

我知道这听起来很疯狂，但我解决了这个问题，方法是将datagrid.Visible属性更改为False，然后更改为True。它会引起很小的眨眼，但对我来说是有效的(至少现在是这样)。

If you would like to keep the DataGridView properties and simply "refresh" it:

如果您想保留DataGridView属性并简单地“刷新”它：

DataTable emptyDt = new DataTable();
dataGridView1.DataSource = emptyDt;

You could encapsulate it in a function for later use.

您可以将其封装在一个函数中以供以后使用。

if you are working with data binging manually the best way to refresh datagridview is dispose the DataTable or Dataset that you used to populate the grid. otherwise how hard you try to clear the rows or remove the rows in Datagridview, it will not refresh the data grid

如果您正在手动处理数据绑定，刷新datagridview的最佳方法是释放您用来填充网格的数据表或数据集。否则，无论您多么努力地清除或移除Datagridview中的行，它都不会刷新数据网格

Try this Code

尝试此代码

private void button_Click(object sender, EventArgs e) {
    if (this.dgInv.DataSource != null) {
        this.dgInv.DataSource = null;
    } else {
        this.dgInv.Rows.Clear();
    }
}

Try this

尝尝这个

DataGridView1.DataSource=ds;
ds.Clear();