Bind TextBox with TextMode DateTimeLocal inside GridView EditItemTemplate in ASP.Net

Hi YulIhnio,

You need to set the formmat to yyyy-MM-ddTHH:mm to assign the value when TextBox TextMode set to DateTimeLocal.

Check the below example.

HTML

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" OnRowDataBound="OnRowDataBound" OnRowEditing="OnRowEditing">
    <Columns>
        <asp:BoundField DataField="Name" HeaderText="Name"></asp:BoundField>
        <asp:TemplateField HeaderText="Date">
            <ItemTemplate>
                <asp:Label ID="lblDate" runat="server" Text='<%# Bind("Date") %>'></asp:Label>
            </ItemTemplate>
            <EditItemTemplate>
                <asp:TextBox ID="txtDate" runat="server" TextMode="DateTimeLocal" Text='<%#Eval("Date","{0:yyyy-MM-ddTHH:mm}") %>'></asp:TextBox>
            </EditItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField>
            <EditItemTemplate>
                <asp:LinkButton Text="Update" runat="server" OnClick="OnUpdate" />
                <asp:LinkButton Text="Cancel" runat="server" OnClick="OnCancel" />
            </EditItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        this.BindGrid();
    }
}

protected void BindGrid()
{
    System.Data.DataTable dt = new System.Data.DataTable();
    dt.Columns.AddRange(new System.Data.DataColumn[] {
            new System.Data.DataColumn("Id"),
            new System.Data.DataColumn("Name"),
            new System.Data.DataColumn("Date",typeof(DateTime)) });
    dt.Rows.Add(1, "John Hammond", new DateTime(2020, 01, 01));
    dt.Rows.Add(2, "Mudassar Khan", new DateTime(2020, 01, 15));
    dt.Rows.Add(3, "Suzanne Mathews", new DateTime(2020, 02, 29, 11, 25, 45));
    dt.Rows.Add(4, "Robert Schidner", new DateTime(2020, 03, 22));
    GridView1.Columns[2].Visible = false;
    GridView1.DataSource = dt;
    GridView1.DataBind();
}

protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        e.Row.Attributes["ondblclick"] = Page.ClientScript.GetPostBackClientHyperlink(GridView1, "Edit$" + e.Row.RowIndex);
        e.Row.Attributes["style"] = "cursor:pointer";
    }
}

protected void OnRowEditing(object sender, GridViewEditEventArgs e)
{
    GridView1.EditIndex = e.NewEditIndex;
    this.BindGrid();
    GridView1.Rows[e.NewEditIndex].Attributes.Remove("ondblclick");
    GridView1.Columns[2].Visible = true;
}

protected void OnUpdate(object sender, EventArgs e)
{
    GridViewRow row = (sender as LinkButton).NamingContainer as GridViewRow;
    string name = (row.Cells[0].Controls[0] as TextBox).Text;
    DateTime dateTime = Convert.ToDateTime((row.FindControl("txtDate") as TextBox).Text);
    GridView1.EditIndex = -1;
    this.BindGrid();
}

protected void OnCancel(object sender, EventArgs e)
{
    GridView1.EditIndex = -1;
    this.BindGrid();
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Me.BindGrid()
    End If
End Sub

Protected Sub BindGrid()
    Dim dt As System.Data.DataTable = New System.Data.DataTable()
    dt.Columns.AddRange(New System.Data.DataColumn() {
                            New System.Data.DataColumn("Id"),
                            New System.Data.DataColumn("Name"),
                            New System.Data.DataColumn("Date", GetType(DateTime))})
    dt.Rows.Add(1, "John Hammond", New DateTime(2020, 1, 1))
    dt.Rows.Add(2, "Mudassar Khan", New DateTime(2020, 1, 15))
    dt.Rows.Add(3, "Suzanne Mathews", New DateTime(2020, 2, 29, 11, 25, 45))
    dt.Rows.Add(4, "Robert Schidner", New DateTime(2020, 3, 22))
    GridView1.Columns(2).Visible = False
    GridView1.DataSource = dt
    GridView1.DataBind()
End Sub

Protected Sub OnRowDataBound(ByVal sender As Object, ByVal e As GridViewRowEventArgs)
    If e.Row.RowType = DataControlRowType.DataRow Then
        e.Row.Attributes("ondblclick") = Page.ClientScript.GetPostBackClientHyperlink(GridView1, "Edit$" & e.Row.RowIndex)
        e.Row.Attributes("style") = "cursor:pointer"
    End If
End Sub

Protected Sub OnRowEditing(ByVal sender As Object, ByVal e As GridViewEditEventArgs)
    GridView1.EditIndex = e.NewEditIndex
    Me.BindGrid()
    GridView1.Rows(e.NewEditIndex).Attributes.Remove("ondblclick")
    GridView1.Columns(2).Visible = True
End Sub

Protected Sub OnUpdate(ByVal sender As Object, ByVal e As EventArgs)
    Dim row As GridViewRow = TryCast((TryCast(sender, LinkButton)).NamingContainer, GridViewRow)
    Dim name As String = (TryCast(row.Cells(0).Controls(0), TextBox)).Text
    Dim dateTime As DateTime = Convert.ToDateTime((TryCast(row.FindControl("txtDate"), TextBox)).Text)
    GridView1.EditIndex = -1
    Me.BindGrid()
End Sub

Protected Sub OnCancel(ByVal sender As Object, ByVal e As EventArgs)
    GridView1.EditIndex = -1
    Me.BindGrid()
End Sub

Screenshot