c# - 如何在回发后将文本保存到绑定(bind)数据库中数据的文本框

Question

下面是组成 GridView 的模板字段之一。标签和文本框的所有值都来自数据库，我想关注这个特定的文本框，这里是 aspx 代码:

<asp:TemplateField HeaderText="ServiceStart" SortExpression="ServiceStart">
        <EditItemTemplate>
            <asp:TextBox ID="txtEditServiceStart" runat="server" type="date" Text='<%# Bind("ServiceStart","{0:d}") %>'  Width="128px"></asp:TextBox>
        </EditItemTemplate>
        <ItemTemplate>
            <asp:Label ID="LblItemServiceStart" runat="server" Text='<%# Bind("ServiceStart","{0:d}") %>' ></asp:Label>
        </ItemTemplate>
</asp:TemplateField>

注意 txtEditServiceStart 是 type=date

这里是程序运行时的初始样子:

图1

现在，当用户点击编辑，编辑文本框的日期(txtEditServiceStart)，文本框看起来像这样:

图2

它显示:mm/dd/yyyy，不显示数据库中的记录。

但是 当用户没有更改该文本框的值并单击:UPDATE(基本上是为了保存更改)时，它将再次加载 gridview，问题是它不会保留文本框的日期，而是默认为:1/1/1900。它应该在哪里显示来自图片 1 的数据再次

请注意，当用户编辑日期时没有问题，它只会更新数据库并且 gridview 将显示新的值/日期。

Basically, I just need to show the data again to the gridview if its not edited by the user instead of showing 1/1/1900

我试过使用 txtEditServiceStart.Attributes.Add("readonly", "readonly"); 但它无法识别我在 C# 代码上的文本框，我认为这是因为我 从数据库绑定(bind) 数据，程序可能无法运行。我也尝试过使用 Eval，而不是 Bind，但仍然无法正常工作

编辑:这是我将数据放在网格上的方式

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

public void BindGrid()
{
    SQLConnect.ConnectionString = ConfigurationManager.ConnectionStrings["dbx"].ConnectionString;
    SQLConnect.Open();
    string sql = "Select  LastName+', '+FirstName+' '+MiddleName  AS EmployeeName, EMPLOYEE.EmpID, ContractNo, ContractDate, ContractDuration, ServiceStart, ContractDetails, ContractValue, Served from EMPLOYEE join SCHOLARSHIPCONTRACT ON EMPLOYEE.EmpID = SCHOLARSHIPCONTRACT.EmpID";
    SqlCommand cmd = new SqlCommand(sql, SQLConnect);
    SqlDataAdapter GridDA = new SqlDataAdapter(cmd);
    DataSet GridDS = new DataSet();
    GridDA.Fill(GridDS);
    //Bind data to gridview
    GridView1.DataSource = GridDS;
    GridView1.DataBind();
    //close connection
    cmd.Dispose();
    SQLConnect.Close();

编辑、取消编辑、更新的代码如下:

protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
{
    if (e.CommandName == "EditRow")
    {
        int rowIndex = ((GridViewRow)((LinkButton)e.CommandSource).NamingContainer).RowIndex;
        GridView1.EditIndex = rowIndex;

        BindGrid();
    }
    else if (e.CommandName == "CancelUpdate")
    {
        GridView1.EditIndex = -1;
        BindGrid();
    }
    else if (e.CommandName == "UpdateRow")
    {
        int rowIndex = ((GridViewRow)((LinkButton)e.CommandSource).NamingContainer).RowIndex;

        string ContractNo = ((TextBox)GridView1.Rows[rowIndex].FindControl("txtEditContractNo")).Text;
        string contractDate = ((TextBox)GridView1.Rows[rowIndex].FindControl("txtEditContractDate")).Text;  
        string contractDuration = ((TextBox)GridView1.Rows[rowIndex].FindControl("txtEditContractDuration")).Text;
        string serviceStart = ((TextBox)GridView1.Rows[rowIndex].FindControl("txtEditServiceStart")).Text;
        string contractDetails = ((TextBox)GridView1.Rows[rowIndex].FindControl("txtEditContractDetails")).Text;
        string contractValue = ((TextBox)GridView1.Rows[rowIndex].FindControl("txtEditContractValue")).Text;
        string DropDownServed = ((DropDownList)GridView1.Rows[rowIndex].FindControl("DropDownServed")).Text;

        AccessLayer.UpdateContract(ContractNo, contractDate, contractDuration, serviceStart, contractDetails, contractValue, DropDownServed);
        GridView1.EditIndex = -1;
        BindGrid();

    }
}

AccessLayer = 更新合约:

public static int UpdateContract(string ContractNo, string ContractDate, string ContractDuration, string ServiceStart, string ContractDetails, string ContractValue, string Served)
{
    string css = ConfigurationManager.ConnectionStrings["dbx"].ConnectionString;
    using (SqlConnection con = new SqlConnection(css))
    {
        string UpdateQuery = "UPDATE SCHOLARSHIPCONTRACT SET ContractDate= @ContractDate, ContractDuration = @ContractDuration, ServiceStart = @ServiceStart, ContractDetails = @ContractDetails, ContractValue= @ContractValue, Served = @Served WHERE ContractNo =@ContractNo";
        SqlCommand UpdateCmd = new SqlCommand(UpdateQuery, con);

        SqlParameter paramOriginalContractNo = new SqlParameter("ContractNo", ContractNo);
        UpdateCmd.Parameters.Add(paramOriginalContractNo);
        SqlParameter paramContractDate = new SqlParameter("@ContractDate", ContractDate);
        UpdateCmd.Parameters.Add(paramContractDate);
        SqlParameter paramContractDuration = new SqlParameter("@ContractDuration", ContractDuration);
        UpdateCmd.Parameters.Add(paramContractDuration);
        SqlParameter paramServiceStart = new SqlParameter("@ServiceStart", ServiceStart);
        UpdateCmd.Parameters.Add(paramServiceStart);
        SqlParameter paramContractDetails = new SqlParameter("@ContractDetails", ContractDetails);
        UpdateCmd.Parameters.Add(paramContractDetails);
        SqlParameter paramContractValue = new SqlParameter("@ContractValue", ContractValue);
        UpdateCmd.Parameters.Add(paramContractValue);
        SqlParameter paramServed = new SqlParameter("@Served", Served);
        UpdateCmd.Parameters.Add(paramServed);
        con.Open();
        return UpdateCmd.ExecuteNonQuery();
    }
}

请建议我可以在 aspx 或 c# 代码上添加的方式/方法谢谢

Answer 1

您的问题是您总是更新您的ContractDate。您必须编辑查询字符串。添加 COALESCE 将为 ContractDate 分配一个值，即:@ContractDate 如果已填充，否则它会分配 ContractDate 的现有值。将方法中的 ContractDate 类型更改为 ?DateTime 它允许您将方法放入 null。当您调用方法时，只需检查文本框是否编辑了日期，如果未设置为空，则将其放入方法中。

 public static int UpdateContract(string ContractNo, DateTime? ContractDate, string ContractDuration, string ServiceStart, string ContractDetails, string ContractValue, string Served)
    {
        string css = ConfigurationManager.ConnectionStrings["dbx"].ConnectionString;
        using (SqlConnection con = new SqlConnection(css))
        {
            string UpdateQuery = "UPDATE SCHOLARSHIPCONTRACT SET ContractDate=COALESCE(@ContractDate=ContractDate), ContractDuration = @ContractDuration, ServiceStart = @ServiceStart, ContractDetails = @ContractDetails, ContractValue= @ContractValue, Served = @Served WHERE ContractNo =@ContractNo";
            SqlCommand UpdateCmd = new SqlCommand(UpdateQuery, con);


            UpdateCmd.Parameters.AddWithValue("ContractNo", ContractNo);
            //Here you have to convert string to DateTime
            UpdateCmd.Parameters.AddWithValue("@ContractDate", ContractDate);
            UpdateCmd.Parameters.AddWithValue("@ContractDuration", ContractDuration);
            UpdateCmd.Parameters.AddWithValue("@ServiceStart", ServiceStart);
            UpdateCmd.Parameters.AddWithValue("@ContractDetails", ContractDetails);
            UpdateCmd.Parameters.AddWithValue("@ContractValue", ContractValue);
            UpdateCmd.Parameters.AddWithValue("@Served", Served);

            con.Open();
            return UpdateCmd.ExecuteNonQuery();
        }
    }