ASP WebForms中如何简化重复创建相同类实例的代码？

下面几种实用方法可以帮你摆脱重复创建控件变量的繁琐：

1. 复用局部变量 #

不需要为每个控件实例都声明新的变量，只要变量已经完成控件的添加工作，就可以重新赋值给新的实例。同时把Label的公共样式配置抽成小逻辑，避免重复设置：

// 只声明一次变量，重复复用
TableRow tempRow;
TableCell tempCell;
TableHeaderCell tempHeader;
PlaceHolder tempPlaceHolder;
Label tempLabel;

// 抽取出Label的公共配置逻辑
Action<Label> setLabelStyle = label => label.Font.Bold = font.Bold;

// 第一行：Tax NUMBER
tempRow = new TableRow();
tempHeader = new TableHeaderCell { Text = "Tax NUMBER" };
tempPlaceHolder = new PlaceHolder { ID = "PhPO" + wo };
tempLabel = new Label { ID = "LblPO" + wo };
setLabelStyle(tempLabel);

tempCell = new TableCell();
tempCell.Controls.Add(tempPlaceHolder);
tempCell.Controls.Add(new LiteralControl("<br/>"));
tempCell.Controls.Add(tempLabel);

tempRow.Controls.Add(tempHeader);
tempRow.Controls.Add(tempCell);
table.Rows.Add(tempRow);

// 第一行：PRINT TIME
tempRow = new TableRow();
tempHeader = new TableHeaderCell { Text = "PRINT TIME" };
tempLabel = new Label { ID = "LblPrintTime" + wo };
setLabelStyle(tempLabel);

tempCell = new TableCell();
tempCell.Controls.Add(tempLabel);

tempRow.Controls.Add(tempHeader);
tempRow.Controls.Add(tempCell);
table.Rows.Add(tempRow);

// 第二行：Part
tempRow = new TableRow();
tempHeader = new TableHeaderCell { Text = "Part" };
tempPlaceHolder = new PlaceHolder { ID = "PhPart" + wo };
tempLabel = new Label { ID = "LblPart" + wo };
setLabelStyle(tempLabel);

tempCell = new TableCell();
tempCell.Controls.Add(tempPlaceHolder);
tempCell.Controls.Add(new LiteralControl("<br/>"));
tempCell.Controls.Add(tempLabel);

tempRow.Controls.Add(tempHeader);
tempRow.Controls.Add(tempCell);
table.Rows.Add(tempRow);

// 第二行：START DATE
tempRow = new TableRow();
tempHeader = new TableHeaderCell { Text = "START DATE" };
tempLabel = new Label { ID = "LblStartDate" + wo };
setLabelStyle(tempLabel);

tempCell = new TableCell();
tempCell.Controls.Add(tempLabel);

tempRow.Controls.Add(tempHeader);
tempRow.Controls.Add(tempCell);
table.Rows.Add(tempRow);

2. 封装辅助方法 #

把重复的控件创建、配置逻辑封装成独立方法，代码会更简洁，后期维护也方便：

// 生成带样式的Label
private Label GetStyledLabel(string id, bool isBold)
{
    return new Label
    {
        ID = id,
        Font = { Bold = isBold }
    };
}

// 生成包含PlaceHolder+换行+Label的单元格
private TableCell GetCellWithPhAndLabel(string phId, string labelId, bool labelBold)
{
    var cell = new TableCell();
    var ph = new PlaceHolder { ID = phId };
    var label = GetStyledLabel(labelId, labelBold);
    
    cell.Controls.Add(ph);
    cell.Controls.Add(new LiteralControl("<br/>"));
    cell.Controls.Add(label);
    
    return cell;
}

// 生成一行并添加到表格
private void AddTableHeaderRow(Table table, string headerText, TableCell cell)
{
    var row = new TableRow();
    var header = new TableHeaderCell { Text = headerText };
    
    row.Controls.Add(header);
    row.Controls.Add(cell);
    table.Rows.Add(row);
}

// 调用方法快速构建表格
AddTableHeaderRow(table, "Tax NUMBER", GetCellWithPhAndLabel("PhPO" + wo, "LblPO" + wo, font.Bold));
AddTableHeaderRow(table, "PRINT TIME", new TableCell { Controls = { GetStyledLabel("LblPrintTime" + wo, font.Bold) } });
AddTableHeaderRow(table, "Part", GetCellWithPhAndLabel("PhPart" + wo, "LblPart" + wo, font.Bold));
AddTableHeaderRow(table, "START DATE", new TableCell { Controls = { GetStyledLabel("LblStartDate" + wo, font.Bold) } });

3. 批量处理结构化数据 #

如果有大量结构相似的行，可以把行的配置信息整理成集合，通过循环批量生成控件，减少重复代码：

// 定义两种行的配置数据
var rowsWithPh = new List<(string Header, string PhId, string LabelId)>
{
    ("Tax NUMBER", "PhPO" + wo, "LblPO" + wo),
    ("Part", "PhPart" + wo, "LblPart" + wo)
};

var simpleRows = new List<(string Header, string LabelId)>
{
    ("PRINT TIME", "LblPrintTime" + wo),
    ("START DATE", "LblStartDate" + wo)
};

// 批量生成带PlaceHolder的行
foreach (var item in rowsWithPh)
{
    var row = new TableRow();
    var header = new TableHeaderCell { Text = item.Header };
    var cell = new TableCell();
    
    var ph = new PlaceHolder { ID = item.PhId };
    var label = new Label { ID = item.LabelId, Font = { Bold = font.Bold } };
    
    cell.Controls.Add(ph);
    cell.Controls.Add(new LiteralControl("<br/>"));
    cell.Controls.Add(label);
    
    row.Controls.Add(header);
    row.Controls.Add(cell);
    table.Rows.Add(row);
}

// 批量生成仅带Label的行
foreach (var item in simpleRows)
{
    var row = new TableRow();
    var header = new TableHeaderCell { Text = item.Header };
    var cell = new TableCell();
    
    var label = new Label { ID = item.LabelId, Font = { Bold = font.Bold } };
    cell.Controls.Add(label);
    
    row.Controls.Add(header);
    row.Controls.Add(cell);
    table.Rows.Add(row);
}

内容的提问来源于stack exchange，提问作者muhammad hazieq