Asp.Net C＃单击按钮后从dataTable gridview删除行

Question

I'm displaying a datatable that selects a number of elements from the database (IncomingsId, Type, Cost, Frequency) and I'm not sure how to delete a row when a button is clicked. I've tried many solutions so far but nothing is working.

Here is the button I have within my Grid view

<asp:TemplateField HeaderText="Delete">  
         <ItemTemplate>  
            <asp:button id="DeleteRowButton" text="Delete Record" onclick="DeleteRowButton_Click" runat="server"/>
         </ItemTemplate>  
     </asp:TemplateField> 

And here is the code behind this page were I am creating the datatable.

 SqlConnection con;

    public _Default()
    {
        con = new SqlConnection(@"MySQLConnection");
    }
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            DisplayRecord();
        }
    }

    public DataTable DisplayRecord()
    { 
        string userId = (HttpContext.Current.User.Identity.GetUserId());

            SqlDataAdapter Adp = new SqlDataAdapter("select * from Incomings where AspNetUsersId = '" + userId +"'", con);

        DataTable Dt = new DataTable();

        Dt.AcceptChanges();
        Adp.Fill(Dt);
            grid1.DataSource = Dt;
            grid1.DataBind();
     return Dt;
    }

    public void DeleteRowButton_Click(object sender, EventArgs e)
    {

    }

Cheers in advance for any help. I'm sure it's a simple resolution

Answer 1

You need a way for your code to know which ID to delete. Here is how I would normally do it:

Replace your button with an ItemTemplate , and add the button in here instead:

    <Columns>
        <asp:TemplateField>
            <ItemTemplate>
                <asp:Button Text="Delete" runat="server" CommandArgument='<%# Eval("userId") %>' CommandName="Delete" />
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>

When you have the button this way, you now have access to a CommandArgument and CommandName attributes. Notice the argument I am passing is Eval("userId") , the command name (as you will see later) is used to recognize what action you want to execute (this could be anything, is just a name).

Replace the CommandArgument with whatever value(s) you want to pass to the server, using the name that came from the database/datasource (I am guessing it would be userId).

Then, to capture this you need to implement the RowCommand event of the GridView, and intercept the correct CommandName :

public void GridView1_RowCommand(Object sender, GridViewCommandEventArgs e)
{
    if (e.CommandName == "Delete")
    {
        string userId = e.CommandArgument.ToString();
        //do something with the id
    }
}

Here you have to make sure the CommandName in your button, matches to whatever action you want to execute in the RowCommand . This should do the trick.

Don't forget to bind the event to your GridView:

<asp:GridView OnRowCommand="GridView1_RowCommand" ID="GridView1" runat="server">
   ...
</asp:GridView>

Answer 2

just use this for the front-end code

    <asp:GridView ID="grid1" OnRowDeleting="OnRowDeleting" DataKeyNames="deleteR" runat="server" AutoGenerateColumns="False"  CellPadding="4"  GridLines="None" style="width:100%"  >  

 <columns>  

    <asp:TemplateField HeaderText="Delete Row">
        <ItemTemplate>
            <asp:Button ID="btnDelete" runat="server" class="btn btn-primary" Text="Delete"  CommandName="Delete" OnRowDataBound="OnRowDataBound" />
        </ItemTemplate>
    </asp:TemplateField>

And have this in behind it:

 protected void OnRowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        int deleteR= Convert.ToInt32(grid1.DataKeys[e.RowIndex].Values[0]);
       //have a sql statement here that add's the parameter ID for the row you want to delete, something like
SqlCommand com  = new SqlCommand ("Delete FROM yourdatabase Where yourID = @yourID"
com.Parameters.AddWithValue("@yourID", yourID)
    }

Answer 3

What you're looking for is indeed a simple solution.
You can use a foreach loop to search all DataRow s within the DataTable for some kind of ID.
Here's an example of what I mean:

String s = "/* IncomingsId for what you want to delete */";
foreach (DataRow r in dt.Rows) {
    if (r["IncomingsId"].ToString().Equals(s)) {
        dt.Rows.Remove(r);
    }
}

Answer 4

Just a quick update for anyone that's helped me, thanks for your advice. Asp.Net has it's own built in AutoGenerateDeleteButton and I set that to true and ran a bit of code behind it. A simple solution that really shouldn't have taken me all day to complete!